Why Safari on iPad doesn't show large jpeg enclosed in IMG tag?

Question

Last time I saw someone asks why Safari on iPad doesn't show some 1920x1440 jpeg with real size & I solved that puzzle. You have to use a progressive-encoded jpeg. However, I find another different problem.

Say, demo.jpg is a progressive-encoded jpeg with 2000x3000 & I upload it to my website. I then access it via url ...demo.jpg, Safari will show it with 2000x3000 size, perfect.

Now I make a most-simple html file named mypic.html. This html has only img tag with src=demo.jpg or src=demo.jpg width=2000 height=3000 inside body. Now I access it via url ...mypic.html. This time Safari show a very small icon of a question mark?

Does anybody know why the latter case fail?

Answer 1

The problem is about the memory available to Safari. The total amount of RAM is just 256MB, and Safari stops showing the image of much smaller size. You need to scale them down.