If images disappear from the Magento site check the below
- Cache refresh
- image path being CASE SENSITIVE
- incorrect image path in catalog_product_entity_media_gallery while porting
- Make sure you have GD installed fine on your server.,.. if not re-install it ..and also disable open_basedir function for this account.
- php_value memory_limit : supports only values in M and not in G you can’t give 1G instead give it as 1024M.
Hope this save lot of time for other Magento users.