Image to C Array Converter (OLED & TFT)

Worked example: a 128×64 logo on an SSD1306

Pick the 128×64 preset, 1-bit output and Horizontal (Adafruit GFX) byte order. Each row of 128 pixels becomes 16 bytes, most significant bit on the left, so the whole screen is 16 × 64 = 1,024 bytes — small enough for an ATmega328P's flash with PROGMEM, and far too big for its 2 KB of RAM without it.

Adafruit_SSD1306 draws that array with drawBitmap(x, y, array, width, height, color). The tool generates the array and #defines; the sketch below is the matching example it offers. If the image comes out as vertical stripes, you picked Vertical pages (the SSD1306's native GDDRAM layout, for writing straight into the display buffer) — switch back to Horizontal.

#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

// Paste the generated array here:
// #define LOGO_WIDTH  128
// #define LOGO_HEIGHT 64
// const uint8_t logo[] PROGMEM = { 0x00, 0x00, ... };  // 1,024 bytes

Adafruit_SSD1306 display(128, 64, &Wire, -1);

void setup() {
  if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {  // 0x3D on some 128x64 modules
    for (;;) {}
  }
  display.clearDisplay();
  display.drawBitmap(0, 0, logo, 128, 64, SSD1306_WHITE);
  display.display();
}

void loop() {}

Why does my bitmap draw garbled?

Almost always a byte-layout mismatch, not a bad image. Diagonal smearing means the width in drawBitmap() doesn't match the array (a 120-pixel-wide image still occupies 15 whole bytes per row — pass the real width, not a rounded one). Mirrored 8-pixel blocks mean the library expects least-significant-bit-first rows (XBM, used by U8g2's drawXBM). An inverted image means your display draws 1 as off: use the Invert option or draw with SSD1306_BLACK on a white background.