On the latest incarnation of the blog, using WordPress, I use a theme called Portfolio Press, which dynamically generates a page based on the posts which are of the “Image” or “Gallery” post format. Except that it was not working correctly – the sizes of the images were different, causing the grid to have a weird layout (float left css anyone?).
I spent a bit of time trying to get the css to do the right thing, got it figured out so that I could cause the pictures to be truncated, but it still did not seem right – the author of the theme had obviously put too much time into the there to have overlooked this use case, what was I doing wrong?
Turns out it is a WordPress (documentation?) defect – when images are uploaded, it is supposed to be creating thumbnails, which are cropped as required, so that the images are all exactly the same size, and of course then the css float works just great. But this was not happening, and when using the Regenerate Thumbnails plugin, I was getting no errors. But the thumbnails were certainly not getting created.
The root cause is that the php-gd extension was not installed – once I installed that, regenerated the thumbnails, and everything now works great. Would have been nice if generating the thumbnails, either during upload, or during the regeneration, had given an error indicating that something was not working…