bitmap_TFT_3.5 with arduino uno

I am working on TFT_3.5 with MCUFRIEND and Adafruit_GFX libraries , I need to display a RGB or black and white picture , I used the function "drawbitmap and drawrgbbitmap" but the picture didn't display on TFT..I am working without sd-card, so I need to convert each picture to hex code,but I don't now what is the best program for TFT to convert any picture to an array of data..Can you help me? Thank you.

Look at the drawBitmap.kbv example.

Look in the data files for an online utility.