Every single other forum I've used has used it's own picture hosting. Maybe some of the membership money could go towards allowing this feature to be enabled on vBulletin.
Just using imgur. Need to sort out adjusting size. Otherwise works great.
Flickr
They are old, and you don't get much space, but they allow 3rd party hosting.
When I do get your attachments to open, the image address is @View attachment 5897
I'm told by some they don't work and by others they do...but this is off Google drive.
When I do get your attachments to open, the image address is @.
I have flikr but for mobile it sucks. Can't get the links.