Question

Basically exactly what the question asks. Do images on a website download the full file before re sizing them. I have a bunch of pictures and I use html to resize the images down to thumbnails to easily display on the page. However, these images take way to long to load while they are only 100px x 100px big. My only explanation is that it is downloading the entire file before re sizing.

Answer 1

Yes. The full image is downloaded.

If the source url is 1000×1000 and you size it on the screen to 100×100, it still has to load the entire image.

You should store the thumbnail at 100×100 and the full size at 1000×1000 and reference each when appropriate.