There is a built in microSD card slot into the breakout, and we can use that to load bitmap images! You will need a microSD card formatted FAT16 or FAT32 (they almost always are by default).
Its really easy to draw bitmaps. However, this is only supported when talking to the display in SPI mode, not 8-bit mode!
It's really easy to draw bitmaps. We have a library for it, Adafruit_ImageReader, which can be installed through the Arduino Library Manager (Sketch→Include Library→Manage Libraries…). Enter “imageread” in the search field and the library is easy to spot:
Lets start by downloading this image of pretty flowers
Copy purple.bmp into the base directory of a microSD card and insert it into the microSD socket in the breakout.
You'll need to connect up the CCS pin to Digital 4 on your Arduino as well. In the below image, its the extra brown wire
You may want to try the SD library examples before continuing, especially one that lists all the files on the SD card
Now upload the File→examples→Adafruit ImageReader Library→ShieldILI9341 example to your Arduino + breakout. You will see the flowers appear!