I am approaching the limits of my hosting plan. I doubled it once from 2 to 4 GB and my site (a popular woodworking community in Hebrew) is getting close to using the disk space
I go through the same process with a website with a lot of traffic, but the public doesn't upload. In fact, there are so many posts per day, that the server stores many images.
Now ... my advice in this case is not to use Dropbox, but another CDN or host that has greater availability for this process. DropBox is for storage. And not for big traffic ... Which with that, will certainly have slow loading and failures. So there is this daily limitation.
There are other services like cloudinary, CDN and hosting specialized in images that can do the same job and without a headache.