const images = await ctx.db.query("images")
  .withIndex("by_userId", q => q.eq("userId", <_id attribute of user>)
  .collect();

const images = await ctx.db.query("images")
  .withIndex("by_userId", q => q.eq("userId", <_id attribute of user>)
  .collect();

images: defineTable({
  userId: v.id("users"),
  ...
}).index('by_userId', ['userId']);

images: defineTable({
  userId: v.id("users"),
  ...
}).index('by_userId', ['userId']);