fix(tip): refine gift presentation

src/app/tip/tip-screen.helpers.ts

@@ -5,6 +5,12 @@ import type {
 
 export const TIP_GIFT_PLACEHOLDER_IMAGE = "/images/tip/medium.png";
 
+const TIP_GIFT_PLACEHOLDER_BY_TIP_TYPE: Readonly<Record<string, string>> = {
+  coffee_small: "/images/tip/small.jpg",
+  coffee_medium: "/images/tip/medium.png",
+  coffee_large: "/images/tip/large.png",
+};
+
 export function formatGiftPrice(
   amountCents: number,
   currency: string,
@@ -25,10 +31,15 @@ export function getGiftImageSources(
   product: GiftProduct | null,
   category: GiftCategory | null,
 ): readonly string[] {
+  const placeholderImage = product
+    ? (TIP_GIFT_PLACEHOLDER_BY_TIP_TYPE[product.tipType] ??
+      TIP_GIFT_PLACEHOLDER_IMAGE)
+    : TIP_GIFT_PLACEHOLDER_IMAGE;
+
   return [
     product?.imageUrl,
     category?.imageUrl,
-    TIP_GIFT_PLACEHOLDER_IMAGE,
+    placeholderImage,
   ].filter(
     (source, index, sources): source is string =>
       Boolean(source) && sources.indexOf(source) === index,