Hi!

So as far as I know and from reading other similar posts, there isn't an inherit means of limiting uploaded files. However this might be possible to achieve via automation chain.

• First create an automation chain in studio
  
• Fetch the input document
  
• Set a variable to get the value from property “file:content” (assuming you are using this field to upload the binary)
  
• Use RunScript operator to use javascript, to take Blob from the variable, and checking its size with Blob.length (will return length in bytes)
  
• Have it where if the length is more than a certain value, set the property “file:content” to be null.
  
• Set a UI alert operator to notify user the file is too big.
  
• Make sure to create an event handler (before document modification) and assign your automation chain to it

This is a very broad solution I know, but I've yet to do this myself. This is just a general idea of what I might do in this situation, so feel free to take this with a grain of salt.