Why shouldn't I use underscore within folder names?

Using underscores within folder names can sometimes cause ambiguity and lead to broken URLs on your website. The reason is that, for example, a folder named u_2 (after the band, of course) can also be parsed as an attempt to "underlay" an asset named "2" under the base asset.

To be on the safe side, you should make sure you stick to at least one of the following principles: 

• Avoid using underscores "_" within names you give to your folders. You can use dash "-" as a delimiter instead.
• Use at least 4 characters before the first underscore occurrence, e.g. abcd_1234.
• Use versions to isolate the public ID from the transformation section.