How to Convert Images to Pixel Art in GIMP

Transforming standard raster artwork into retro pixel art in GIMP is a simple process that involves downscaling the image to reduce resolution, restricting the color palette to achieve a classic aesthetic, scaling the image back up using the correct interpolation method to preserve hard pixel edges, and performing manual cleanup. This guide walks you through the exact, step-by-step workflow required to convert any high-resolution image into stylized pixel art.

Step 1: Prepare and Downscale the Image

Pixel art relies on a low pixel grid. To convert your high-resolution artwork, you first need to drastically reduce its dimensions.

  1. Open your image in GIMP by navigating to File > Open.
  2. Go to Image > Scale Image.
  3. In the dialog box, change the width and height to a low resolution (such as 64×64, 128×128, or a similar size depending on the level of detail you want).
  4. Set the Interpolation method to Cubic or Linear to blend the details smoothly during the downscale.
  5. Click Scale.

Step 2: Reduce the Color Palette (Indexing)

Classic pixel art relies on limited color palettes. Reducing the number of colors simplifies the artwork and creates an authentic retro look.

  1. Go to Image > Mode > Indexed.
  2. In the Indexed Color Conversion window, select Generate optimum palette and enter a maximum number of colors (e.g., 16, 32, or 64). Alternatively, choose Use custom palette and select a retro palette such as Game Boy, CGA, or Commodore 64.
  3. Under the Dithering options:
    • Select None for flat, clean pixel clusters.
    • Select Floyd-Steinberg (normal) if you want a retro cross-hatch shading effect.
  4. Click Convert.

Step 3: Upscale for Display

To export and share the pixel art without modern photo viewers blurring the result, you must scale the image back up using nearest-neighbor interpolation.

  1. Go to Image > Scale Image.
  2. Multiply the current width and height by an integer (such as 400%, 800%, or 1000%) to bring the image back to a standard viewing size (e.g., 1024×1024 or 1920×1080).
  3. Set the Interpolation dropdown strictly to None. This disables anti-aliasing and ensures each pixel remains a crisp, square block.
  4. Click Scale.

Step 4: Clean Up and Refine

Automated conversion often leaves isolated or messy pixels (noise) that need manual correction.

  1. Go to Image > Mode > RGB to allow full editing flexibility.
  2. Select the Pencil Tool (not the Paintbrush Tool, as the Pencil tool paints with hard, anti-aliasing-free edges).
  3. Set the brush size to match the scaled pixel size or work at a 1:1 scale before the final upscale.
  4. Use the Color Picker Tool to sample existing colors and clean up outlines, remove stray pixels (orphans), and refine shading.

Step 5: Export Your Pixel Art

  1. Navigate to File > Export As.
  2. Choose PNG as the file format to ensure lossless compression with no compression artifacts.
  3. Click Export.