(Thanks go to Elmar Sonnenschein for his feedback and support.) 2: V1.2.1 contains minor improvements, e.g.
through serial monitor software (for example Arduino IDE serial monitor). If the bitmaps do not count towards heap, that graph naturally wont show them. 8: V1.3.0 optimizes UI updates to save CPU resources and also includes a new menu and small fixes. (flexible static memory controller) to drive a TFT color LCD. NOTE: to get a width and height of image you can look at mWidth and mHeight fields in MAT in attributes section as shown in image in question. The profiler graph shows heap memory usage. If you didn't, you can try to change some other parameters in "Load Image from Raw Data" dialog.
First, you need to download and install GIMP.