I'm currently experimenting with some display shields. Showing bitmaps on a display is what interests me most. For this I bought a couple of different displays with SD card slot (including Adafruit 1947, 1651, Waveshare 13506, 10684). What struck me is that it takes a relatively long time to display bitmaps on all the displays I have tested, i.e. at least 1 second for an image with a size of 320 x 240 pixels. Some even take several seconds to do this. You can see how the image builds up line by line from top to bottom.
Now my question: I would like to load/show the images as quickly as possible, i.e. without the slow picture build-up. I would aim for a maximum loading time of 100 ms for an image of 320 x 240 pixels. I have about 100 pictures on the SD card. Does anyone have a recommendation for me which display is best (fastest) for this? I work with an Arduino Mega 2560 and would like to use a display with a size of approx. 3.5 inches (2.8 to 4 inches possible).