This is caused by performing an anti-bot lockout on your account for our image provider. Effectively google interprets a large number of new image load requests for a specific account as a scraper and decides to serve up 403’s instead of the images. The issue will usually resolve after 5 minutes or so. We are working on a different method of handling images whereby the client will directly load them without using Cloudinary. Some users may still get the anti-bot lockout for the images but it should be greatly reduced.
Unfortunately google drive is turning out to be a sub-optimal place to host your images.