Colorbox downsizing in Firefox (and Chrome and Safari)

What width and height values do the images have...
... which look as expected? (are they lower/the same/greather than 540x405?)
... which are downsized? (as of #0 this is 540x405)

If you have a downsized image, click on the image, to get to the details page. Replace the word "detail" in the current url to "lightbox" and open the new url. Is the image still downsized?

As it affects only one browser, are you sure, that it is no cache-problem?

I'm having the same problem.
Tried different themes.
Using:
Media Gallery 7.x-1.0-beta7
Media 7.x-1.0-rc3
Colorbox plugin 1.3.19 (had 1.3.17 same problem)

#2 Does it work in all browsers except in Firefox, as the issue starter said? Can you give an answer to the questions in #1?
- Is there a public installation available with this problem?

#3
Yes its only a Firefox problem. I cleared everything on Firefox including cache.
Which look is expected? width of 500px, height is width dependent. So greater than the displayed dimensions.

See it here: http://csphoto.seleqta.com/node/1

It seems to be a Theme issue.

File: http://csphoto.seleqta.com/sites/all/themes/arctica/arctica/styling/css/...
There you can find the following lines:

img {
    -moz-box-sizing: border-box;
    height: auto;
    max-width: 100%;
}

If i remove height: auto; it works for me. Can you confirm that?

Yes, removing height:auto fixed it.
Thank you.

Removing that one line CSS didn't fix the problem for me.

Here is my solution for the problem:
https://github.com/jackmoore/colorbox/issues/210

Hope it helps!

Could this issue be closed?

#5 solved my problem. I also add that I had some minor problems with styles when I was using default skin of colorbox.
When I chose example1 - everything looked much better.

Here is an example of usage: http://med4kids.pl/med4kids-galeria

Thanks Moloc for Your help.

regards,
Marcin

Thank you for this.

Once I clicked on the image
the empty colorbox at full size would appear
then shrink
then the image would be inserted and cut off since the colorbox itself was small
If I was to come back to it, then it might open with image at the correct size.

I had to remove "height:auto;" from my theme(s):
profiles/openatrium/modules/panopoly/panopoly_images/panopoly-images.css
profiles/openatrium/themes/oa_radix/assets/screen.css

I am not sure what ramifications this might have.
It might be better to define a colorbox class for each image passed into colorbox and make sure the css settings override that instead of just the id img.

thanks for this fix. It was driving me nuts. Removing height:auto from the theme did the trick.

CSS trick seems to solve the problem , but has secondary effects in other site images

Have tried

https://www.drupal.org/node/1851848#comment-6916220

, despite being a a radically diferent option in terms of format&design
it works fine for me.

Thanks