Product images not displaying sometimes in safari

This is very random, but occasionally in safari, some main product images do not display at first. It's just blank where the picture should be. When the mouse goes over the area, the image then displays.

I'm wondering if this has anything to do with it: I've looked at the files, and I noticed that the they are in gif format, but I uploaded them as jpg. For example, image.jpg becomes image.jpg.gif. Why is Hikashop changing them to .gif? When I go to the _files table to edit the image extension and remove the .gif, and change the filename in the media folder directly via ftp, the standard barcode image is displayed instead of the the image file. I'm wondering if the images were in .jpg format, safari would do better with them.

Hi,

Which version of HikaShop do you have ?
What you can try is upload via ftp, then use our new (from 2.1.0) image selector to choose the images.

For information, all the images extensions are not changed. If you upload a .jpg, it will stay a .jpg file.
Don't have you installed a component/plugin which is editing your pictures ?