Get Image File Size From Base64 String

I’m working on a python web service. It calls another web service to change the picture of a profile.

It connects to another web service. This web service can only accept pictures that are 4 MB or smaller.

I will put the checking in the first web service. It uses PIL to check if the base64 string is a valid image. However, how do I check if the base64 string will create a 4 MB or smaller image?

Answer

Multiply the length of the data by 3/4, since encoding turns 6 bytes into 8. If the result is within a few bytes of 4MB then you’ll need to count the number of = at the end.