• This application can convert .jpg, .jpeg, .png and .gif files with a size of max. 1 MB.
• After conversion it gives you back 2 output files: a .png file and a C64 .prg program file.
• The output .png file gives you an idea of the conversion result.
• The output .prg file contains the converted image as well and can display it on a C64.
• Download the .prg file and run it it on the C64 or an emulator. To exit the program and return to the BASIC prompt, press RUN/STOP + RESTORE simultaneously.
• Conversion mode:
  • Dithering: applies dithering, by combining different colors of the C64 palette, it gives the impression of another color.
  • Closest color: chooses per pixel of the original image the closest color available in the chosen palette. Typically this results in rather ugly images.
• Palette:
  • Full color: all the 16 colors of the C64 are used.
  • RGB: Black, white, red, green and blue colors are used.
  • Black/white: only black and white are used.
  • Greyscale: Black, white and the 3 greys of the C64 palette are used.
  • Custom: Custom choice of 2 up to 16 colors of the C64 palette.
• Resizing mode:
  • Fitted: If the original image has a different width/height ratio than supported by the C64 graphics mode, the application will fit the complete image while keeping the correct ratio by either adding black borders to the left and right sides or the top and bottom sides of the original image. Fine tune this mode further with the Aspect ratio option.
  • Cropped: If the original image has a different width/height ratio than supported by the C64 graphics mode, the application will use the maximum possible screen space with the correct ratio by cropping the original image. The center of the image is kept, by either cropping the left and right sides or the top and bottom sides. Fine tune this mode further with the Aspect ratio option.
  • Stretched: In this mode the original image is stretched so that it gets displayed entirely and will fill the whole screen. Orginal images that deviates too much from the ideal ratio, will look distorted. The image will not be cropped, neither borders will be added. In this mode the Aspect ratio option has only effect on the generated .png image and not on the C64 program.
• Aspect ratio:
  • Original: The used aspect ratio is 8:5. The resulting C64 .prg may not look fine, especially on the NTSC version of the C64. A circle will ook rather like an ellips.
  • PAL: Conversion is optimized to show the image on a PAL version of the C64.
  • NTSC: Conversion is optimized to show the image on a NTSC version of the C64.

• Multicolor bitmap (320x200)
• This means an effective bitmap of 160x200 pixels, the image will be expanded by a factor 2 in the horizontal direction when displayed.
• 1 background color.
• Max 3 additional colors per character block of 8x8 pixels (after expansion).
• C64 has only a palette of 16 fixed colors.
• Due to the above limitations of the C64, artefacts are likely be visible in the converted image.
• No sprites used.
• To do: add the option to choose between different color schemes. Currently only a highly saturated scheme is supported.

Here you find an example where the same image is converted with different settings. The aspect ratio is in all cases the 'Original' one. Depending on the settings the result is more or less appealing. This depends also also on the level of detail and different colors of the original image. You may need to play around with the different settings.

Original image

Dithering, Full color

Closest color, Full color

Dithering, Greyscale

Dithering, Black/white

Closest color, RGB

Dithering, Custom (Black, White, Yellow, Violet, Cyan)

• V5 - 2022, Dec 28:
  • Add option to fit the image into the screen by adding borders.
• V4 - 2022, Dec 24:
  • Add option to stretch the image over the whole screen.
• V3 - 2022, Sept 11:
  • Add option to choose a custom set of colors to do the conversion with.
• V2 - 2022, Sept 1:
  • Minor bugfix, not affecting the output results.
  • Speed up of the conversion.
  • Additional help information.
• V1 - 2018, Sept 1:
  • Initial release of the img2c64mc online tool.