Reducing & Increasing Thumbnail Size

Mr Lucky

Well-known member
If I reduce the thumbnail size, Does it resize the existing thumbnails smaller, or ,make brand new ones from the media?

The reason I ask is say I then decide I want them back to what they were, if it resizes the smaller thumbnails back up to the larger size, they are going to lose a bit of quality, so I'm hoping each resize generates from original media. Is that correct?

Chris D

XenForo developer
Staff member
Just a thing to note first:

Changing the thumbnail size will not affect the number of media items shown per row. For example, if your current thumbnail size is 300 pixels, and it displays 3 per row (like here: then reducing the thumbnail size down to 200 pixels will not automatically start showing 4 per row.

The actual way to change that is to change the settings in XFMG: Responsive Design.


It basically links up to the break points in XenForo's responsive design. In a general sense:

Narrow is a mobile phone
Medium is a large phone/small tablet
Wide is a larger tablet/small desktop
Default is desktop

Certainly you'll want to make sure you get these right first before deciding on a thumbnail size.

But, yes, to answer your question, you would have to rebuild the thumbnails after you change the value and doing so would reproduce the thumbnails from the original image.

Mr Lucky

Well-known member
Hmmm, I have changed Items per row default and wide to 5, but it is still showing 3. Is there somewhere else I need to change this as well?

EDIT: Ignore this: I edited the wrong style


Active member
I did as shown, changed the (default) thumbnail size from 300 x 300 to 80 x 80 and let rebuilt the thumbnails as brogan suggested but no effekt....still ugly big thumbnails in the media gallerie preview... I also reloaded the site to get it out of the browsers cache...

Any ideas what i do wrong ?


Edit: Found it out now. Had to change responsive style properties too....
Now it looks smooth but imho this should be changed so that the visible thumbnail size does not depend on how many thumbs i put in a row. It should correspond to the settings (80 x 80) i made regardless how many thumbs i have in a row...
Last edited: