You can store images and files in folders in the design studio. But these folders are not "typed"and you cannot ensure that people will place them correctly. And also, as you have noticed, the folders in the design studio are not reflected in the public URL of the images.
There are quite a few ideas to vote for in the community:
- Store images/files in program or create a File/Image program token type
- Offer SFTP access to Marketo file storage
- Restrict file types per folder in Design Studio
- Make the right to create folders in design studio/image and file section a specific permission
- Make the image and file folders real in URLs, not just virtual, and simplify the URL
Some good ideas there
We've elected to go for a prefix on all assets.