To use this script you have to adjust the values in the cursor definition. The script produces an update statement because I wanted to add the images after I inserted the main data of the table, but you can adjust the script to generate insert value.
Note that the output script gets really large (thousands of lines) when you have a lot of images and really big images. Because of this the script inserts the output script into a table instead of logging it with dbms_output for example. Depending on your image sizes and amount this script could not be a good solution because it can take some time to transform the raw data back to blobs.
If you have a better solution / feedback feel free to comment under the gist.
Thanks to Kees Vlek who made a blogpost about how to export static workspace files where I got the code on how to transform the blobs to raw data from.