Steps:

1. Download any Picture with Letters from FreePik.com

2. For every Letter:

2.1 Cut the Letter with Rect Select Tool

2.2 Copy Selected Area

2.3 Paste as new Picture

2.4 Image-> Crop To Content

2.5 Save as Example "A.xcf"

3. Install Davids Batch Processor

3.1 Input: Add all XCF Files

3.2 Output as BMP

3.3 Open Folder in Explorer and Show Headers width and Height in Explorer.

3.4 Now look ordered as width and height to max  width and height

3.5 Maybe edit Letters, very Big "W"

4.1 Add BMPs from Folder in Batch Processor

4.2 Go To Resize, Enable, absolute Centered with Padding Background Black

4.3 Resize to Width and Height from heighest and Widest Letter.

5. Open IrfanView Batch Renaming

5.1 Rename Pictures ordered alphabetical to P#

6. Convert Picture to Bin or/and Hex File

6.1 In my case i have written a Little Javatool thats converts all Pictures starting with "P#.BMP" in same Folder. The Tool converts all Pictures in 3Byte/Pixel RGB24 for ILI9488 Rawdata.

For testing i use Picinfo.bin in Spiff, for Final Fastwriting i stored the bin as constant Bytearray .. 480x320px*3Bytes fired out in 80ms via 40Mhz SPI. With this Trick the Big Letters draws very fast by 100FPS.

Video with fastwrite Function, Same Procedure for Pictures (Funny Clock Timer) :