Ran into some weird trouble with the Nextgen Gallery WordPress plugin. Couldn’t find a lot of information to help solve the problem, so I thought I’d write up the experience for anyone else having a similar problem.

In the admin area, you can create custom thumbnails for your images. An image is supposed to pop up that you can drag a thumbnail over. But for some reason, when I opened up the window to create a thumbnail, the image didn’t appear. The image was coming up blank, like if you link to an image that isn’t there.

The actual image was there on the server, so that wasn’t a problem. I followed the trail a bit and figured out that the image for the thumbnail creation process was created by a script, nggshow.php (part of the Nextgen plugin). The script itself was working. It fetched all the information, put it in an object, and then it was supposed to spit out an image.

The problem was that the final output is supposed to be a jpeg. But, some white space was added at the top of the file, so the output was corrupted. The jpeg was there, but the browser couldn’t render it because of the added white space at the top of the file. I don’t know where exactly that was coming from, but it was added in somewhere in the Nextgen Gallery plugin files.

I tried to go through, eliminate any extra lines outside the php tags, and get rid of the white space. I eliminated one of the two newline characters that was in the output, but I couldn’t find the second. After pulling my hair for a while, I realized that I was working with an older version of Nextgen Gallery (1.5.3). I updated to the most recent (1.5.5), and it worked fine. Doh.

So… simple solution. Upgrade to the latest version of the plugin.