This is issue number 3 (February-March 1988) of a short-lived, UK comic book magazine published bi-monthly by Marvel Comics in London. Marvel had nothing to do with producing the magazine's contents; they simply translated and adapted issues of the French "Inspecteur Gadget" magazine published by Greantori for several years in the 80s. Greantori's comics were adapted from TV episodes, and were for the most part pretty awful: Badly paced storytelling coupled with amateurish drawings which were usually traced off of stills from the given episode. The one saving grace was the cover art, which almost always looked terrific. The covers were also based on existing artwork - model sheets, promotional art or episode motives - but were much better drawn than anything inside.
I quite like the above cover for Marvel's third issue. Yeah, the characters are posed somewhat generically, and there are some off-model colors, but Gadget, Penny and Brain still look very, very nice. I also like the gallery of faces in the left-hand margin, and the title logo here looks noticeably better than the classic American merchandising logo (with the possible exception of the squeezed "O", which seems to be redrawn from the "U" in the French "Inspecteur Gadget" logo).
The entire cover for Marvel's No. 3 was clearly taken from the French Greantori publication "album n°2" which I believe collected several stories from the standard magazine issues. I don't know the exact publication date of the French album, but here it is for comparison:
And that's not all for this motive, either. To continue the game of connect-the-dots: in 1993, the German publisher Bastei-Verlag used it for a one-off "Inspektor Gadget" comic published as issue 9 of their magazine series "Bastei Fernseh-Comic" ("television comic"). This time, however, the actual Greantori artwork was not used. Bastei's cover is apparently traced from the Greantori art instead, for whatever reason (specifically from the Marvel cover, I think, looking at the juxtaposition of elements and Gadget's speech bubble) - and it has to be said that the inking and character drawing is not nearly as accomplished as on the French and British covers. Still interesting to see, though.
(With thanks to GC for providing the magazine images seen in this post.)