Image Error when uploading and then site goes down

Hello,

Whenever I upload images (most of the time) I get the error uploading image message and the image does not finish uploading. Straight after this my site seems to malfunction and go down and I can’t get on any page on the site.. every page is blank. Does anyone have any ideas what this is?

I am using GoDaddy as my host.
I am using the MHMagazine theme.
This theme automatically re-sizes images for different thumbnails.

I hope you guys can help!