For hosting common files it's ok. Also it is on Android too do, great to transfer files between your Windows and your phone. But if you want better security you have to subscribe a monthly offer.
miniPaint - Online graphics editing tool use HTML5 technologies like Canvas, Offline support, Drag and Drop.
Dropbox - Online Sync and File Sharing
JugiPaint - JugiPaint is a painting software with diverse tools for various types of illustration work.
Google Drive - Access and sync your files anywhere
Ultimate Paint - Ultimate Paint is a full-featured 32-bit Windows graphics program for image creation, viewing and...
Mega - Secure File Storage and collaboration