Http500 After Uploaded 7Mb Image

During testing uploaded a large size (7mb) image and after a few seconds of processing got a http500 page. Now, the home page is not loading (http500). Admin page seems to load,but if I filer my products so that search results will include a page with that large image - getting an http500 error, otherwise search seems to work fine. Increased memory to 128m,upload file size is at 50m.

Here Is a message in the log: PHP Fatal error: Allowed memory size of 268435456 bytes exhausted (tried to allocate 9000 bytes) in /home3/public_html/art5/app/functions/fn.images.php on line 636

How can bring website back to live? Thank you.

If you provide us with the temporary FTP access, we can check the issue on your server

Try 384 or 512 for memory.

Since I did not had many products, I simply re-installed cs-cart. Thank you everyone for your replies!