An error occurred while copying image, check your memory limit. prestashop

This is not related to prestashop. You have to increase memory limit in php.ini file in your server.

I'm using fatcow as my service provider. Here the steps for solve this

1. Log in to your FatCow Control Panel.
2. Go to CGI and Scripted Language Support.
3. Click PHP Scripting.
4. Your php.ini file is displayed in a text box at the bottom. Click Edit if you cannot edit the php.ini file text.
5. Locate the following block of code within your php.ini file:
   ; Maximum amount of memory a script may consume (128MB)
   ; http://php.net/memory-limit
   memory_limit = 32M
6. Modify the highlighted value for memory_limit as desired (example: 35M, or 40M, or 45M).
7. Click Save.