diff --git a/cmd/wallart-server/main.go b/cmd/wallart-server/main.go
index 35b01e9..5e6364f 100644
--- a/cmd/wallart-server/main.go
+++ b/cmd/wallart-server/main.go
@@ -112,19 +112,22 @@ func handleUpload(w http.ResponseWriter, r *http.Request) {
 			return
 		}
 
+		// Implement GIF disposal modes
+		// Normally you woud want to use draw.Src instead of draw.Over for the first of each of these.
+		// But in this particular application, we want transparency to become black.
+		draw.Src.Draw(dst, imgRect, image.Black, image.Point{})
 		switch inputGif.Disposal[i] {
 		case gif.DisposalNone:
-			draw.Src.Draw(dst, previousImg.Rect, previousImg, image.Point{})
+			draw.Over.Draw(dst, previousImg.Rect, previousImg, image.Point{})
 			draw.Over.Draw(dst, img.Rect, img, img.Rect.Min)
 			undisposedImg = dst
 		case gif.DisposalBackground:
-			draw.Src.Draw(dst, backgroundImg.Rect, backgroundImg, image.Point{})
+			draw.Over.Draw(dst, backgroundImg.Rect, backgroundImg, image.Point{})
 			draw.Over.Draw(dst, img.Rect, img, img.Rect.Min)
 		case gif.DisposalPrevious:
-			draw.Src.Draw(dst, undisposedImg.Rect, undisposedImg, image.Point{})
+			draw.Over.Draw(dst, undisposedImg.Rect, undisposedImg, image.Point{})
 			draw.Over.Draw(dst, img.Rect, img, img.Rect.Min)
 		default:
-			draw.Src.Draw(dst, img.Rect, image.Black, image.Point{})
 			draw.Over.Draw(dst, img.Rect, img, img.Rect.Min)
 		}