Images wont upload properly

Hi all,

I am hoping that someone can assist me, i am having issues with uploading images to wordpress, both via the media browser and through FTP.

When i upload an image via the media browser, it sometimes shows a red error box in the right hand top corner of the media browser, but does not say what the error is. When i then navigate away from the page, and then back again, the image has uploaded but in the media browser/ library it only shows as a small dot (much like a full stop). If i click on view the image it only shows the small dot.

If i upload an image on FTP it does not show up in the media browser.

I have searched and searched through the forums but cant seem to find the answer. I have tried to reset all the plugins as well as deactivating them all and then activating them one by one and trying to upload images in between, but to no avail.
I have also changed the theme to the stock one and still the same issues.

I have also tried this on 2 seperate domains but still the same.

I am running the enfold theme, and i have made sure it has been updated to the newest version following the upgrade to 3.9.2

The strange thing is that despite the images showing as just small dots in the media browser, they do show up on posts on the website if viewed on a pc or mac browser but they dont show up on a tablet.

Can anyone give me a hand to resolve this please?

Toby