Gallery Question

Once in awhile I will make gallery posts like this https://regretfulmorning.com/2009/03/tribute-to-tanks-in-action/

The problem is: After someone clicks the image, the picture remains small, so they end up having to click it twice to get the larger image. I could resolve this by linking directly to the file but I don’t like how that looks.

Is there any way to make it so the gallery pictures come out larger (at least 555 px) when ppl click on them?