Photo attachments and storage limits

[Kaspeer]

Hey
I've been using Roundcube to send high-res photos of my 50p and £2 pieces to some fellow collectors for valuation. Usually it works fine but I've noticed a weird lag lately where the thumbnails don't generate or the upload just hangs halfway. My storage quota says I have space left but the behavior says otherwise especially with these larger image files. I've tried resizing them and clearing my cache without much success. I'm definitely not a server expert so maybe I missed a simple setting in the interface. Any of you had similar issues when dealing with lots of attachments?

[SKaero]

Is there any errors either in the Roundcube log <RC directory>/logs/errors or in the browsers JS console?