I improved the intro up to “Previous article about G’MIC on Pixls.us”.
Remarks (maybe I am too thorough 
)
– I find it an odd choice that there is no vertical space between certain paragraphs, which is present in the original French. I would either make it one paragraph or two with the space in between. Just a minor quibble.
– The word libre. I suppose free is good enough for our purposes, but certain proponents of free software, etc., prefer to use libre in English as well.
– There are still diction problems in the article. I don’t have time to sift through. Sometimes it is a wrong word choice. Other times it is a translation inconsistency. In the latter case, it would be nice if expressions were translated the same throughout the article.