newcomers | Image embed ettiquite question (Reply)

I'm working on a post that discusses use of color in a series' character designs and peripheral media, so I have to embed lots of images in order to make my point. I've been designing "photosets" by hand using css and html. The simplest way for me to make these image sets is to have a grid of images, where all the images in a row shrink and grow to match the width of the visible post-space.

However, some images, even if placed in a "photoset" with this technique, still stretch a page vertically quite badly. For example, a full image of a character standing in place with no background is often very vertical. This ends up visually "overwhelming" the text, which I don't want to do. Yes, putting the image under a cut prevents it from being annoying in reading page and journal-page views, but I also want the image to look nice while visible, and not overwhelm the paragraphs above and below it.

Is there any common etiquette for the maximum height (in pixels) of an embedded in-post image in a post published to a community?