You can now add a custom logo in the beg dialog of your scripted plug-in.

When the Active Page Item Developer Toolkit 1.0.46 will be released, it will contain an updated APIDTemplate with the proper placeholders to insert your PNG file name. Until that happens, you will need to manually adjust your source code in the APIDTemplate-derived InDesign spln project file.

Put a 80(w)x100(h) pixel PNG file with a unique file name next to your .spln file - e.g. at Rorohiko, we might use a file called

com.rorohiko.textexporter.logo.png

or something like that. The file name must be globally unique; it can actually be stored anywhere below the InDesign application folder, but the logical place is to store it next to the .spln file, perferrably inside a wrapper folder. Keep in mind that from 1.0.46 onwards, the .spln can be stored 'loose' and does not need to be in the vicinity of the APIDToolAssistant any more - so it makes sense to group .spln files and their PNG files into a single folder.

Then open your InDesign project file, and use the Active Page Item Developer to change the plugin controller ExtendScript - look for a set of lines like this:

thePluginSourceItem.setDataStore("$LICENSE_URL$",kLicenseURL);
thePluginSourceItem.setDataStore("$LICENSE_MESSAGE$",kLicenseMessage);
thePluginSourceItem.setDataStore("$DEMO_TIMED_OUT_MESSAGE$",kTimedOutMessage);
thePluginSourceItem.setDataStore("$SPLNVERSION$",kSPLNVersion);

and add a line similar to (replace the file name with whatever you've used):

thePluginSourceItem.setDataStore("$SPLNLOGO$", "com.rorohiko.textexporter.logo.png");

The beg dialog will only appear for non-free spln files - compile the spln, quit and restart InDesign, and you should see your beg dialog with your custom logo appear.