I know that not everything can be done and there are physical limitations to the nonvolatile memory and also as to the programmer’s time.
I think a nice feature would be able to add you own widgets in the HMI builder that would be selectable in the dropdown list box. I know that it is possible with the API currently, but that would require programming knowledge on part of a user and that is a very powerful tool, but if you have the availability of perhaps 9 additional slots in the widgets for a graphic file and name that could be loaded similar to a custom background image. That way, an average user could make a better HMI without any programming knowledge.
You could even set up”storage of public images" along with http://www.embeddedcc.com/hmi/dflt.png
You could set the limit on the size of the graphic as well as type. I would assume that the existing ones are small image files (80 x 80 pixels)
From what I have been able to ascertain is that the GuiPix class will accept
a. .jpg
b. .bmp
c. .png
d. .gif
e. .svg
I would assume that the WidgetSel “name” could be like “User Widget 1” etc.
As an example, you might create small image of a burner with flames. The non asserted could the “greylight.gif” or maybe another generic “box” image, but asserted the custom “burner with flames” image file.