diff --git a/discord/url.go b/discord/url.go
index 50bab02..52f0d1a 100644
--- a/discord/url.go
+++ b/discord/url.go
@@ -1,4 +1,34 @@
 package discord
 
+import "strings"
+
+type ImageType string
+
+const (
+	// AutoImage chooses automatically between a PNG and GIF.
+	AutoImage ImageType = "auto"
+
+	// JPEGImage is a JPEG image type.
+	JPEGImage ImageType = ".jpeg"
+	// PNGImage is the PNG image type.
+	PNGImage ImageType = ".png"
+	// WebPImage is the WebP image type.
+	WebPImage ImageType = ".webp"
+	// GIFImage is the GIF image type.
+	GIFImage ImageType = ".gif"
+)
+
+func (t ImageType) format(name string) string {
+	if t == AutoImage {
+		if strings.HasPrefix(name, "a_") {
+			return name + ".gif"
+		}
+
+		return name + ".png"
+	}
+
+	return name + string(t)
+}
+
 type URL = string
 type Hash = string