already got it Rated 5 out of 5 stars

ok forget it, "great" was not the ideal word ... Anyway, I renamed the image from PNG to JPG and it worked: D

PS: here are the 5 stars;)

This review is for a previous version of the add-on (0.27.1-signed.1-signed). 

First thanks for the update & higher rating! I'm a bit surprised - renaming png to jpg would not actually change an image's format. Your image program might open it fine if it can open both png and jpg files AND knows to check image header first (most modern image programs do that). But some image programs will complain that the file is actually a png file incorrectly named jpg. So are you sure this renaming way fits your need?

suggestion Rated 4 out of 5 stars

Hi! your extension really work great, but can you add the option for save in jpg?
I need resize the image before save in my pc and only can I do with this addon, but if I can will save in jpg would perfect

PS: I'm sorry if my english is bad

This review is for a previous version of the add-on (0.27.1-signed.1-signed). 

It's doable, but I'm not a fan of the practice where a user gives a "great" addon 4-star instead of 5-star and then ask the author to fulfill a request, particularly when the request is not in the original scope of the addon (it's not intended to be a flexible format converter).

Anyway, I can see the need might arise, but the devil's in the details. Are you asking that the image ALWAYS be saved in jpg, or only the originally-jpg images saved in jpg? Some of this addon's users might always wanted it to be png, some might want it to be always saved in original format. I'll think about the UI.