Photo grids are a relatively new feature in the forums, where if you upload multiple photos it will make a little grid layout instead of having them all in a row.
This has surprised some people who were used to the previous behavior. Discourse currently does not have a way to change this, but they are working on a site setting where the site admin can change the default for everyone.
Note that you can always add or remove the [grid] tag in your posts regardless of the default setting.
Once they ship this feature, should we set the default to:
It upsets me more than it should that the grid-view crops (trims?) the photos. For example, the last image (the “Not Sara” one) in this meme post by Smacky has the left and right edges of its text trimmed, hurting the readability. But if you click the image’s grid-view thumbnail, the full image has the full text and a bit of margin as well.