Change 117161 had a related patch set uploaded by Mooeypoo:
Enforce width-only default size only on larger images

https://gerrit.wikimedia.org/r/117161

Change 117161 merged by jenkins-bot:
Enforce width-only default size only on larger images

https://gerrit.wikimedia.org/r/117161

I can still reproduce this bug for the same image on that page when I switch from "Set to default size" to "Set Custom Size"

Change 118231 had a related patch set uploaded by Mooeypoo:
Deal with images whose size is smalled than default

https://gerrit.wikimedia.org/r/118231

Change 118231 merged by jenkins-bot:
Deal with images whose size is smalled than default

https://gerrit.wikimedia.org/r/118231

Verified the fix on :http://en.wikipedia.beta.wmflabs.org/w/index.php?title=12thmarchchrome&veaction=edit

Verified the fix on test2:https://test2.wikipedia.org/w/index.php?title=User:RYasmeen_%28WMF%29/sandbox&veaction=edit

Verified the fix in production: https://en.wikipedia.org/wiki/User:RYasmeen_%28WMF%29/sandbox?veaction=edit

This bug is happening again now in Betalabs and test2 for the image File:Ló_heraldika.png

I can't replicate on master with the same image [[File:Ló_heraldika.png|thumb]]

It appears in the proper size, which is much smaller than the default.

This is still happening:

Getting the error message "Size values are invalid" when I switch to custom from default tab.Also, also the default size is appearing as 220x245 px where as the full size of the image is 71x79 px (smaller than the default size)

Just tested this again with the new MWImageModel, and it seems this bug is fixed.

I tested on both Ló_heraldika.png and FS_barnstar.png with quick changes to the size (as before). Works properly for me in labs.

Provisionally marking as FIXED, then. :-)

Yes, I checked it with those images on Betalabs and looks like it got fixed with https://gerrit.wikimedia.org/r/#/c/120808/

verified the fix in test2

Verified the fix in production