Error message when uploading a photo

I’m getting the following message when I try and upload a relatively small file:
Fatal error: Out of memory (allocated 68681728) (tried to allocate 14592 bytes) in /home/joyous1z/public_html/wp-includes/media.php on line 254

I’ve recently switched from a PC to a Mac and I’ve noticed when I save photo files, the file ext “jpg” is not on the file name, but it’s definitely a jpg. When I upload photos from my PC they work. The files are 300-500kb only, so they are pretty small.

HELP!