I have used this script recently, here are my feedback:

1) If the screenshot has been uploaded successfully but failed to attach to CL. It will be awesome if the script could store the SHA1 somewhere else so that re-run won't re-upload the pictures.
 
2) The script is slow if there're lots of pictures . Some screenshot might contains multiple string but I have to upload them multiple times for each string. It will be awesome if it's uploaded only once. (Detect duplicated pictures)
 
3) Chrome vs Chromium. Most of time, the difference is tiny. Rebuild Chrome to capture screenshot seems lots of work. I don't have a good suggestion for this. But hopefully there is a better solution here.
 
4) Right now, there is only one SHA1 the file. It's hard for ppl to know if it's the right picture. It will be awesome if there is a google drive link I could take a look.