Can't Upload pictures

having an issue uploading pictures onto my website. I host a website for a magazine and uploading new pictures and content is a must.

I have read up on other related issues, was advised to deactivated all activated widgets and plug-in apps then upload the pic, this helped me update a picture but as soon as I re-activated the widgets and plugins the same thing happened… do I have to de-activate all widgets and re-activate them just to change pictures or upload new ones?

How can I fix this issue permanently?

Thanks Prishan Latchman