[simoncoggins]

I've seen something similar with a PNG file for user supplied profile image [1]. The image was a 10000x10000 all black PNG image which compresses to a pretty small file size.

Unless you validate the image dimensions as well as the file size it may cause problems, for instance when GD is used to try to resize it exhausted the memory limit.

[1] https://bugs.launchpad.net/mahara/+bug/784978

[tripzilch]

You can do somewhat better if you host it on a server with gzip compression. Since the PNG has a max dictionary size for the compression, it doesn't optimally compress out all the redundancy. But because the left-over redundancy also forms a repeating pattern (since the black is the same all over the image), gzip shrinks it even further.

I got slightly better results even by doing this with a JPG image, probably because it's based on 8x8 blocks. I used the colour red, but I don't think that matters much.

Correction, looking back to my results, it seems the PNG was smaller after all: png32512.png.gz is 36,077 bytes (a 32000x32000 JPG gzips to about 41k). I forget how I came to the 32512x32512 limit, maybe it was by trial & error, the largest size a browser still opens (probably tested on Firefox and Opera, didn't use Chrome at the time).

I also asked some friends with powerful (lots of memory) computers to try out a webpage that would load this image many times, with unique GET parameters to prevent caching, but apart from loads of harddisk access and maxing the CPU for a bit until they closed the tab, nothing crashy happened (and of course I did inform them what could happen and told them to save any work).

Reliably crashing a browser on a sufficiently high-end (say, gaming) PC, I haven't been able to do it since at least 5 years or so. I might have done better if I'd own a high-end computer myself, of course :) I remember it used to be as easy as making a webpage with 200 full-page DIV layers stacked at 1% opacity :-P

[frenchman_in_ny]

This strikes me as being similar to the Black Fax attack [1] from years ago.

[1]https://en.wikipedia.org/wiki/Black_fax

[rorrr]

Out of curiosity I just made two images:

15,000 x 15,000: http://i.imgur.com/WzCyE.png

50,000 x 50,000: http://i.imgur.com/kgmHu.png

Both FF and Chrome refuse to open the second one. IE does something weird. Both Opera and Safari figure out the size correctly, but don't display the image.

[b3tta]

With Firefox (15.0.1) I get some really, really strange results with the second image.

When I opened it the first time, or everytime I press Ctrl+Shift+R it works, but it shows the URL, and a litte icon in the upper left corner: http://i.imgur.com/B7jFE.png

If I press F5 or Ctrl+R it doesnt work, just as you said.

[syassami]

Wow, the first one crashed my chrome browser. Thanks for sharing

[m4rkuskk]

In case safari crashes and you won't be able to open it, sudo rm -rf ~/Library/Caches/com.apple.Safari did it for me.