I'm moving this to QA since the functionality per the task description is already in place (until the feature flags are in place, this can be tested by right clicking on the task card and open in new tab or copy the link address).

Current image viewer:

Checked in betalabs - works as expected.

@mewoph - a minor note: the vertical scrolling is present even for full-screen mode (but not for all images).
Couple of examples where the vertical scrolling is present:

• https://commons.wikimedia.org/wiki/File:Voorgevel_-_Groningen_-_20093578_-_RCE.jpg

full-screen view:

• https://commons.wikimedia.org/wiki/File:Layer-by-Layer.png

full-screen view:

Moving for @RHo review.

Change 753023 had a related patch set uploaded (by Sergio Gimeno; author: Sergio Gimeno):

[mediawiki/extensions/GrowthExperiments@master] Add an image: limit image height to prevent vertical scroll

https://gerrit.wikimedia.org/r/753023

@Etonkovidova I created a tentative patch to solve the vertical scroll issue. I couldn't test with the particular images that you posted, could you point me to an article that has this problem in beta?

Change 753023 merged by jenkins-bot:

[mediawiki/extensions/GrowthExperiments@master] Add an image: limit image height to prevent vertical scroll

https://gerrit.wikimedia.org/r/753023

Moving to QA for scrolling fix

Great. Thanks for checking @Etonkovidova