Emacs eats up my memory while viewing images

[Danny YUE]

Hi guys,

I was viewing some (well, lots of) old images using image+ in Emacs.
Then I noticed that it opens new image slower and slower.
I ran command `free -h` and noticed that my memory was almost totally
consumed.
Then I killed Emacs and memory consumption dropped to normal level.

I suspect there is something wrong with it, because when I press "N" for
`image-next-file`, the old image file is removed from buffer list, thus
the memory consumed by it *should* be released...

Any help is appreciated.

Danny