Fatal error in backend, but not in frontend?

[jflash]

Intresting... (PS My english is bad, but...) I log in backend with Super Users privileges and use Phoca Gallery. If i upload single image (3 MB, dimensions 3456 x 2304 px) in backend, i got a message „Fatal error: Allowed memory size of 33554432 bytes exhausted (tried to allocate 3456 bytes) in /home/xxx/public_html/administrator/components/com_phocagallery/libraries/phocagallery/image/imagemagic.php on line ...“
So i read forums and found few tutorials how to increase memory_limit but it does not help me. Then i tried to reduce picture size (down to 500 kb) – still dosnt help. Then i reduce picture height (proportional with height), to 3000px – still error, to 2600px – error, to 2500px – NO ERROR! And Phoca creates thumbnail, and medium pictures. So, i think my server GD Library configuration does not allow bigger images...
BUT! Now i log in frontent and use Phoca Gallery User Control Panel with Registered user access. I upload singel unchanged image (3 MB, dimensions 3456 x 2304 px), Phoca uploads it and creates all thumbnails without error!
What is wrong with backend upload? Is really prolem in server (mis)configuration? I have Joomla! 1.7 and Phoca Gallery 3.0.2, memory_limit=64MB.

[jflash]

Today it works... Why? I dont know...

[Jan]

Ok

[jflash]

But, i ask from hoster. They moved my site to better server. So, this show me - it was some server misconfiguration or too low performance!