Render image diffs in the but tui details pane

Cargo.toml

@@ -380,6 +380,20 @@ serde_json = { opt-level = 3 }
 # This one is special as we can run into debug assertions otherwise.
 # They have a time, but let's chose the time instead of always being hit by it.
 gix-merge = { opt-level = 3, debug-assertions = false }
+# Image decoding and resizing for the TUI's image diffs is far too slow unoptimized.
+image = { opt-level = 3 }
+png = { opt-level = 3 }
+fdeflate = { opt-level = 3 }
+miniz_oxide = { opt-level = 3 }
+flate2 = { opt-level = 3 }
+zune-jpeg = { opt-level = 3 }
+zune-core = { opt-level = 3 }
+image-webp = { opt-level = 3 }
+gif = { opt-level = 3 }
+tiff = { opt-level = 3 }
+weezl = { opt-level = 3 }
+color_quant = { opt-level = 3 }
+byteorder-lite = { opt-level = 3 }
 
 [profile.release.package.but-installer]
 opt-level = "z" # Optimize for size instead of speed

crates/but/Cargo.toml

@@ -148,6 +148,18 @@ itertools.workspace = true
 self_cell.workspace = true
 rand.workspace = true
 ratatui-textarea = "0.8.0"
+ratatui-image = { version = "11", default-features = false, features = [
+    "crossterm",
+] }
+image = { version = "0.25.10", default-features = false, features = [
+    "png",
+    "jpeg",
+    "gif",
+    "webp",
+    "bmp",
+    "ico",
+    "tiff",
+] }
 arboard = { version = "3.6.1", default-features = false }
 textwrap = "0.16.2"
 syntect = { version = "5.3.0", default-features = false, features = [

crates/but/src/command/legacy/diff2.rs

@@ -151,6 +151,11 @@ impl DiffLineWriter for DiffWriter<'_> {
                 }
                 writeln!(self.out)?;
             }
+            DetailsLine::Image(_) => {
+                // This writer never reports image support, so image lines are not produced
+                // for it; keep the placeholder in case that ever changes.
+                writeln!(self.out, "Binary file - no diff available")?;
+            }
             DetailsLine::SectionSeparator => {
                 writeln!(self.out)?;
             }