To add your own 24 bit colour picture using a header file pic.h
First resize your picture to a 240x135 pixels and save as a PNG file using Paint of similar picture editing software.
Then use the online converter to get a pic.c file by going to http://www.rinkydinkelectronics.com/t_imageconverter565.php
input your pic.png and select convert to pic.c file.
download the pic.c
Then rename the pic.c file you downloaded to pic.h by show in folder and then right clicking on the pic.c file and selecting rename (ignore the file type warning and click YES)
Then place the pic.h in the libraries directory and your sketch directory.
Include the following line in your sketch
#include "pic.h"
To display the picture in you sketch add the following code :-
tft.init()
tft.setRotation(1);
tft.fillScreen(TFT_BLACK);
tft.setCursor(0, 0);
tft.setTextDatum(MC_DATUM);
tft.setSwapBytes(true);
tft.pushImage(0, 0, 240, 135, pic);
// Add a delay if required to view
delay(5000);