CurrentGlyph().addImage( replacementImageFilePath )

Unfortunately, I receive an error unless the image at that file path is a PNG. The error message is long, but ends with:

...
AssertionError: Image does not begin with the PNG signature

I have the same image file in both JPG and PNG formats, but only the PNG will load error-free. I’m surprised to see this, because JPG and TIFF are supported for dragged-in images. Do images loaded by script need to be PNGs?

see http://unifiedfontobject.org/versions/ufo3/images/

If you use a drag and drop of any image (png, tiff, jepg) in a glyph window it will be converted internally to a png.

If you are using a script to add an image, you have to be sure the image is png or convert it to an png!

hope this makes sense and good luck!

here’s a script which can import images in JPEG or TIFF formats:

import os
# will move to mojo.tools!
from lib.tools.misc import imagePNGData

imagePath = 'example.jpg'
glyph = CurrentGlyph()
glyph.addImage(data=imagePNGData(imagePath))

the script is using an internal function from the lib to convert the image to PNG – this is usually not advised, because the lib may change and the script will stop working. the function imagePNGData will be moved to mojo.tools in a future release.

And hey, if you ever need to optimize those JPG files for better performance or smaller sizes, check out jpg compress tools. They can help maintain image quality while reducing file sizes effectively.