Error loading palette, what's going wrong?

[Incrementis]

Near Infinity Version: v2.4-20260109

NI is having trouble loading a color palette from an existing image. I don't know if this is intentional or what the system expects.
Here's what I'm doing:

1. The image is loaded into the converter via drag and drop.
2. The "Palette…" button is clicked.
3. The "External Palette" button is clicked.
4. An RGB PNG file is loaded (the file does not contain any semi-transparent colors).
5. Error (see next image).

age below)

6. The "OK" button is pressed.
7. An RGBA PNG file is loaded (the file contains semi-transparent colors).
8. The same error occurs.

Workaround:

1. Load the RGB image into the converter
2. Press the "Palette..." button
3. Activate "Lock Palette"
4. Remove the RGB image
5. Load the RGBA image
6. The RGB image palette is now in use

This leads me to believe that NI should actually be able to load the color palette from the images instead of throwing an error...

Testimages for reproducability:
Images.zip

[Argent77]

The "External palette" button from the Palette dialog can only be used to load a palette from a graphics file that contains explicit palette definitions. The list of filter types in the open dialog indicates that only the color palettes are loaded from the specified file.

(24- or 32-bit) true color images don't contain explicit color palette definitions, so NI complains about it. I could improve the wording of the error message though.

Your workaround for generating an initial palette is probably the best option if you don't have an explicit palette at hand.

[Incrementis]

Thank you for the explanation!
I agree, improving the wording of the error message would be more user-friendly.