.obj to .glb - big file size due to .jpg

I want to make a web platform with functions that can convert .obj files with .jpg texture into .glb files.

I used GLTFExporter.js and it works pretty well on the local side. However, when I use the same files to test on the website (1. upload obj and jpg 2.convert both into URL 3.run convert functions), the size of .glb file gets larger. After several tests, it turns out that there is something wrong with the jpg file after it converts into url. My assumption is that JPG url is DOMString which stores data in a different mode than a normal JPG file. Do you have any suggestions about the conversion problem? Is there a way to reduce the converted glb file size? Thank you in advance for your reply.

Can you share an example of the .obj, .jpg, and .glb files? Are you using the ‘binary’ option on GLTFExporter?