You could avoid special handling for solid-color backgrounds by using the image-as-background setup plus a solid-color image. And that image might as well be 1x1 px, right? But if image tiling is a loop that goes “open image, draw to buffer, close image” then you’re waiting on the filesystem about a million times

This makes sense to me. But unfortunately, according to a comment above, using a smaller image and tiling it is actually the solution to the slow loading.