Problems with PNG image display

[xietao]

I want to display an 18*18 png image, but I can't display it, and when I debug, I found that I need to apply 36k heap memory to decode using the png decoder, where sizesizeof(PNG_decode) requires 35k, and my image data only needs 154 bytes of memory. This situation makes my MCU unable to display png images, how can I fix it?

[Joel Bodenmann]

If you only work with an 18x18 image, PNG is the wrong format to choose.
For such as small image, you're better of using something like BMP or even the NATIVE format.

PNG does have a minimum overhead of 34k. See the "RAM usage" section in the documentation: https://wiki.ugfx.io/index.php/Images#PNG