Are Fairy Tail Covers the Same in Japanese and English?
For the main series, the answer holds across all 63 volumes: the English editions use the same cover paintings Mashima drew for Kodansha, so a Japanese volume and its English twin show the same image. What the English publishers changed is everything around the painting: the logo's setting, the author credit's language, taglines, trim and paper.
The pairs below put the evidence side by side, the first volume and the last, in both markets.
VOLUME 1 · 2006 / 2008


So the answer is yes for the art and no for the object: an English volume 1 and a Japanese volume 1 show the same painting, but they are different books in trim, paper, dressing and text, and a shelf can tell them apart without opening either.
VOLUME 63 · 2017 / 2018


The pattern held for the whole run: Kodansha USA kept Mashima's covers, so the Japanese and English sets shelve as visual twins. The documented differences are the ones visible here, language, logo setting, and publisher's furniture.