diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 4f8d2671c..4f07faf2f 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -478,3 +478,63 @@ jobs:
           useDaemon: false # sometimes fails on short jobs
       - name: typos check
         run: nix develop -c typos
+
+  test-pkg-linux:
+    strategy:
+      fail-fast: false
+      matrix:
+        pkg: ["wuffs"]
+    name: Run pkg/${{ matrix.pkg }} tests on Linux
+    runs-on: namespace-profile-ghostty-sm
+    needs: test
+    env:
+      ZIG_LOCAL_CACHE_DIR: /zig/local-cache
+      ZIG_GLOBAL_CACHE_DIR: /zig/global-cache
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Setup Cache
+        uses: namespacelabs/nscloud-cache-action@v1.2.0
+        with:
+          path: |
+            /nix
+            /zig
+
+      # Install Nix and use that to run our tests so our environment matches exactly.
+      - uses: cachix/install-nix-action@v30
+        with:
+          nix_path: nixpkgs=channel:nixos-unstable
+      - uses: cachix/cachix-action@v15
+        with:
+          name: ghostty
+          authToken: "${{ secrets.CACHIX_AUTH_TOKEN }}"
+
+      - name: Test ${{ matrix.pkg }} Build
+        run: |
+          nix develop -c sh -c "cd pkg/${{ matrix.pkg }} ; zig build test"
+
+  test-pkg-macos:
+    strategy:
+      fail-fast: false
+      matrix:
+        pkg: ["wuffs"]
+    name: Run pkg/${{ matrix.pkg }} tests on macOS
+    runs-on: namespace-profile-ghostty-macos
+    needs: test
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      # Install Nix and use that to run our tests so our environment matches exactly.
+      - uses: cachix/install-nix-action@v30
+        with:
+          nix_path: nixpkgs=channel:nixos-unstable
+      - uses: cachix/cachix-action@v15
+        with:
+          name: ghostty
+          authToken: "${{ secrets.CACHIX_AUTH_TOKEN }}"
+
+      - name: Test ${{ matrix.pkg }} Build
+        run: |
+          nix develop -c sh -c "cd pkg/${{ matrix.pkg }} ; zig build test"
diff --git a/nix/zigCacheHash.nix b/nix/zigCacheHash.nix
index d4d451e03..60e9e58a4 100644
--- a/nix/zigCacheHash.nix
+++ b/nix/zigCacheHash.nix
@@ -1,3 +1,3 @@
 # This file is auto-generated! check build-support/check-zig-cache-hash.sh for
 # more details.
-"sha256-ot5onG1yq7EWQkNUgTNBuqvsnLuaoFs2UDS96IqgJmU="
+"sha256-njCce+r1DPTKLNrmrD2ObEoBS9nR7q03hqegQWe1UuY="
diff --git a/pkg/wuffs/build.zig b/pkg/wuffs/build.zig
index 36bb5a07c..438f714d3 100644
--- a/pkg/wuffs/build.zig
+++ b/pkg/wuffs/build.zig
@@ -30,4 +30,36 @@ pub fn build(b: *std.Build) !void {
         .file = wuffs.path("release/c/wuffs-v0.4.c"),
         .flags = flags.items,
     });
+
+    const unit_tests = b.addTest(.{
+        .root_source_file = b.path("src/main.zig"),
+        .target = target,
+        .optimize = optimize,
+    });
+
+    unit_tests.linkLibC();
+    unit_tests.addIncludePath(wuffs.path("release/c"));
+    unit_tests.addCSourceFile(.{
+        .file = wuffs.path("release/c/wuffs-v0.4.c"),
+        .flags = flags.items,
+    });
+
+    const pixels = b.dependency("pixels", .{});
+
+    inline for (.{ "000000", "FFFFFF" }) |color| {
+        inline for (.{ "gif", "jpg", "png", "ppm" }) |extension| {
+            const filename = std.fmt.comptimePrint("1x1#{s}.{s}", .{ color, extension });
+            unit_tests.root_module.addAnonymousImport(
+                filename,
+                .{
+                    .root_source_file = pixels.path(filename),
+                },
+            );
+        }
+    }
+
+    const run_unit_tests = b.addRunArtifact(unit_tests);
+
+    const test_step = b.step("test", "Run unit tests");
+    test_step.dependOn(&run_unit_tests.step);
 }
diff --git a/pkg/wuffs/build.zig.zon b/pkg/wuffs/build.zig.zon
index 126e43aba..d84d6957e 100644
--- a/pkg/wuffs/build.zig.zon
+++ b/pkg/wuffs/build.zig.zon
@@ -3,8 +3,13 @@
     .version = "0.0.0",
     .dependencies = .{
         .wuffs = .{
-            .url = "https://github.com/google/wuffs/archive/refs/tags/v0.4.0-alpha.8.tar.gz",
-            .hash = "12200984439edc817fbcbbaff564020e5104a0d04a2d0f53080700827052de700462",
+            .url = "https://github.com/google/wuffs/archive/refs/tags/v0.4.0-alpha.9.tar.gz",
+            .hash = "122037b39d577ec2db3fd7b2130e7b69ef6cc1807d68607a7c232c958315d381b5cd",
+        },
+
+        .pixels = .{
+            .url = "git+https://github.com/make-github-pseudonymous-again/pixels?ref=main#d843c2714d32e15b48b8d7eeb480295af537f877",
+            .hash = "12207ff340169c7d40c570b4b6a97db614fe47e0d83b5801a932dcd44917424c8806",
         },
 
         .apple_sdk = .{ .path = "../apple-sdk" },
diff --git a/pkg/wuffs/src/error.zig b/pkg/wuffs/src/error.zig
index 609deec9c..c75188718 100644
--- a/pkg/wuffs/src/error.zig
+++ b/pkg/wuffs/src/error.zig
@@ -1,3 +1,13 @@
 const std = @import("std");
 
+const c = @import("c.zig").c;
+
 pub const Error = std.mem.Allocator.Error || error{WuffsError};
+
+pub fn check(log: anytype, status: *const c.struct_wuffs_base__status__struct) error{WuffsError}!void {
+    if (!c.wuffs_base__status__is_ok(status)) {
+        const e = c.wuffs_base__status__message(status);
+        log.warn("decode err={s}", .{e});
+        return error.WuffsError;
+    }
+}
diff --git a/pkg/wuffs/src/jpeg.zig b/pkg/wuffs/src/jpeg.zig
new file mode 100644
index 000000000..63ca428d1
--- /dev/null
+++ b/pkg/wuffs/src/jpeg.zig
@@ -0,0 +1,146 @@
+const std = @import("std");
+const Allocator = std.mem.Allocator;
+const c = @import("c.zig").c;
+const Error = @import("error.zig").Error;
+const check = @import("error.zig").check;
+
+const log = std.log.scoped(.wuffs_jpeg);
+
+/// Decode a JPEG image.
+pub fn decode(alloc: Allocator, data: []const u8) Error!struct {
+    width: u32,
+    height: u32,
+    data: []const u8,
+} {
+    // Work around some weirdness in WUFFS/Zig, there are some structs that
+    // are defined as "extern" by the Zig compiler which means that Zig won't
+    // allocate them on the stack at compile time. WUFFS has functions for
+    // dynamically allocating these structs but they use the C malloc/free. This
+    // gets around that by using the Zig allocator to allocate enough memory for
+    // the struct and then casts it to the appropriate pointer.
+
+    const decoder_buf = try alloc.alloc(u8, c.sizeof__wuffs_jpeg__decoder());
+    defer alloc.free(decoder_buf);
+
+    const decoder: ?*c.wuffs_jpeg__decoder = @ptrCast(decoder_buf);
+    {
+        const status = c.wuffs_jpeg__decoder__initialize(
+            decoder,
+            c.sizeof__wuffs_jpeg__decoder(),
+            c.WUFFS_VERSION,
+            0,
+        );
+        try check(log, &status);
+    }
+
+    var source_buffer: c.wuffs_base__io_buffer = .{
+        .data = .{ .ptr = @constCast(@ptrCast(data.ptr)), .len = data.len },
+        .meta = .{
+            .wi = data.len,
+            .ri = 0,
+            .pos = 0,
+            .closed = true,
+        },
+    };
+
+    var image_config: c.wuffs_base__image_config = undefined;
+    {
+        const status = c.wuffs_jpeg__decoder__decode_image_config(
+            decoder,
+            &image_config,
+            &source_buffer,
+        );
+        try check(log, &status);
+    }
+
+    const width = c.wuffs_base__pixel_config__width(&image_config.pixcfg);
+    const height = c.wuffs_base__pixel_config__height(&image_config.pixcfg);
+
+    c.wuffs_base__pixel_config__set(
+        &image_config.pixcfg,
+        c.WUFFS_BASE__PIXEL_FORMAT__RGBA_PREMUL,
+        c.WUFFS_BASE__PIXEL_SUBSAMPLING__NONE,
+        width,
+        height,
+    );
+
+    const destination = try alloc.alloc(
+        u8,
+        width * height * @sizeOf(c.wuffs_base__color_u32_argb_premul),
+    );
+    errdefer alloc.free(destination);
+
+    // temporary buffer for intermediate processing of image
+    const work_buffer = try alloc.alloc(
+        u8,
+
+        // The type of this is a u64 on all systems but our allocator
+        // uses a usize which is a u32 on 32-bit systems.
+        std.math.cast(
+            usize,
+            c.wuffs_jpeg__decoder__workbuf_len(decoder).max_incl,
+        ) orelse return error.OutOfMemory,
+    );
+    defer alloc.free(work_buffer);
+
+    const work_slice = c.wuffs_base__make_slice_u8(
+        work_buffer.ptr,
+        work_buffer.len,
+    );
+
+    var pixel_buffer: c.wuffs_base__pixel_buffer = undefined;
+    {
+        const status = c.wuffs_base__pixel_buffer__set_from_slice(
+            &pixel_buffer,
+            &image_config.pixcfg,
+            c.wuffs_base__make_slice_u8(destination.ptr, destination.len),
+        );
+        try check(log, &status);
+    }
+
+    var frame_config: c.wuffs_base__frame_config = undefined;
+    {
+        const status = c.wuffs_jpeg__decoder__decode_frame_config(
+            decoder,
+            &frame_config,
+            &source_buffer,
+        );
+        try check(log, &status);
+    }
+
+    {
+        const status = c.wuffs_jpeg__decoder__decode_frame(
+            decoder,
+            &pixel_buffer,
+            &source_buffer,
+            c.WUFFS_BASE__PIXEL_BLEND__SRC,
+            work_slice,
+            null,
+        );
+        try check(log, &status);
+    }
+
+    return .{
+        .width = width,
+        .height = height,
+        .data = destination,
+    };
+}
+
+test "jpeg_decode_000000" {
+    const data = try decode(std.testing.allocator, @embedFile("1x1#000000.jpg"));
+    defer std.testing.allocator.free(data.data);
+
+    try std.testing.expectEqual(1, data.width);
+    try std.testing.expectEqual(1, data.height);
+    try std.testing.expectEqualSlices(u8, &.{ 0, 0, 0, 255 }, data.data);
+}
+
+test "jpeg_decode_FFFFFF" {
+    const data = try decode(std.testing.allocator, @embedFile("1x1#FFFFFF.jpg"));
+    defer std.testing.allocator.free(data.data);
+
+    try std.testing.expectEqual(1, data.width);
+    try std.testing.expectEqual(1, data.height);
+    try std.testing.expectEqualSlices(u8, &.{ 255, 255, 255, 255 }, data.data);
+}
diff --git a/pkg/wuffs/src/main.zig b/pkg/wuffs/src/main.zig
index 3f03a4158..f5fc01501 100644
--- a/pkg/wuffs/src/main.zig
+++ b/pkg/wuffs/src/main.zig
@@ -1,2 +1,9 @@
+const std = @import("std");
+
 pub const png = @import("png.zig");
+pub const jpeg = @import("jpeg.zig");
 pub const swizzle = @import("swizzle.zig");
+
+test {
+    std.testing.refAllDeclsRecursive(@This());
+}
diff --git a/pkg/wuffs/src/png.zig b/pkg/wuffs/src/png.zig
index 3a3ac9a35..4597c6ccb 100644
--- a/pkg/wuffs/src/png.zig
+++ b/pkg/wuffs/src/png.zig
@@ -2,6 +2,7 @@ const std = @import("std");
 const Allocator = std.mem.Allocator;
 const c = @import("c.zig").c;
 const Error = @import("error.zig").Error;
+const check = @import("error.zig").check;
 
 const log = std.log.scoped(.wuffs_png);
 
@@ -29,11 +30,7 @@ pub fn decode(alloc: Allocator, data: []const u8) Error!struct {
             c.WUFFS_VERSION,
             0,
         );
-        if (!c.wuffs_base__status__is_ok(&status)) {
-            const e = c.wuffs_base__status__message(&status);
-            log.warn("decode err={s}", .{e});
-            return error.WuffsError;
-        }
+        try check(log, &status);
     }
 
     var source_buffer: c.wuffs_base__io_buffer = .{
@@ -53,11 +50,7 @@ pub fn decode(alloc: Allocator, data: []const u8) Error!struct {
             &image_config,
             &source_buffer,
         );
-        if (!c.wuffs_base__status__is_ok(&status)) {
-            const e = c.wuffs_base__status__message(&status);
-            log.warn("decode err={s}", .{e});
-            return error.WuffsError;
-        }
+        try check(log, &status);
     }
 
     const width = c.wuffs_base__pixel_config__width(&image_config.pixcfg);
@@ -102,11 +95,7 @@ pub fn decode(alloc: Allocator, data: []const u8) Error!struct {
             &image_config.pixcfg,
             c.wuffs_base__make_slice_u8(destination.ptr, destination.len),
         );
-        if (!c.wuffs_base__status__is_ok(&status)) {
-            const e = c.wuffs_base__status__message(&status);
-            log.warn("decode err={s}", .{e});
-            return error.WuffsError;
-        }
+        try check(log, &status);
     }
 
     var frame_config: c.wuffs_base__frame_config = undefined;
@@ -116,11 +105,7 @@ pub fn decode(alloc: Allocator, data: []const u8) Error!struct {
             &frame_config,
             &source_buffer,
         );
-        if (!c.wuffs_base__status__is_ok(&status)) {
-            const e = c.wuffs_base__status__message(&status);
-            log.warn("decode err={s}", .{e});
-            return error.WuffsError;
-        }
+        try check(log, &status);
     }
 
     {
@@ -132,11 +117,7 @@ pub fn decode(alloc: Allocator, data: []const u8) Error!struct {
             work_slice,
             null,
         );
-        if (!c.wuffs_base__status__is_ok(&status)) {
-            const e = c.wuffs_base__status__message(&status);
-            log.warn("decode err={s}", .{e});
-            return error.WuffsError;
-        }
+        try check(log, &status);
     }
 
     return .{
@@ -145,3 +126,21 @@ pub fn decode(alloc: Allocator, data: []const u8) Error!struct {
         .data = destination,
     };
 }
+
+test "png_decode_000000" {
+    const data = try decode(std.testing.allocator, @embedFile("1x1#000000.png"));
+    defer std.testing.allocator.free(data.data);
+
+    try std.testing.expectEqual(1, data.width);
+    try std.testing.expectEqual(1, data.height);
+    try std.testing.expectEqualSlices(u8, &.{ 0, 0, 0, 255 }, data.data);
+}
+
+test "png_decode_FFFFFF" {
+    const data = try decode(std.testing.allocator, @embedFile("1x1#FFFFFF.png"));
+    defer std.testing.allocator.free(data.data);
+
+    try std.testing.expectEqual(1, data.width);
+    try std.testing.expectEqual(1, data.height);
+    try std.testing.expectEqualSlices(u8, &.{ 255, 255, 255, 255 }, data.data);
+}