Hi today users are reporting across #wikimedia-operations and #wikipedia-en that thumbnails are not showing. Soon after reporting it thumbnails start working but then others doint.

[19:15:15] <jynus> many thumbs dont load properly
[19:15:35] <jynus> but it is not reproducible
[19:16:59] <jynus> probably the image backend

[23:06:59] <matt_flaschen> I've been getting
[23:07:01] <matt_flaschen> Request from 173.161.178.89 via cp2026 cp2026, Varnish XID 346270525
[23:07:02] <matt_flaschen> Error: 503, Service Unavailable at Fri, 21 Apr 2017 22:04:24 GMT
[23:07:10] <matt_flaschen> and other images on Commons full-resolution images.

[23:16:46] <eddiegp> Having that too, opening random images in full size view on commons results in (1) loading them as espected (2) firefox saying "can't show image because it contains errors" (3) getting 503 Wikimedia error page shown (pick one from 1-3 randomly with same probability each).