*sigh* So Tellico 1.2.1 went out the door with a bug that would cause it to use the wrong temporary directory for writing images. So if you were opening data files that included the images in there with them, Tellico would write those images out to /tmp/kde-*******/tellico****** and then forget where it put them, essentially. (KDE uses unique directory names for tmp files)
It will likely cause data loss if you save the file, and certain options are turned on. If that happens to you, please accept my apologies. Tellico does save backup files with the ~ extension, so look for one of those and open it.
Tellico 1.2.2 is available with a fix. I know it's just one day after 1.2.1 was released, and I certainly hope I don't keep introducing bugs like this every day. But this is an important bug fix. Version 1.2 did not have the bug.