GBA Image Upscaler

This tool upscales Game Boy Advance screenshots (240x160) to 600x400 resolution, perfect for 640x480 retro handhelds. Rather than using traditional blurry bilinear scaling, it uses a specialized algorithm that maintains pixel clarity while smoothing diagonal edges.

How it works:

• Each 2x2 pixel block from the original image is expanded into a 5x5 block
• Corner pixels are preserved exactly, maintaining crispness
• Edge and center pixels are intelligently filled by choosing the darkest neighboring pixel, which helps preserve the original artwork's line work and prevents unwanted blurriness

This approach results in cleaner upscaling compared to standard scaling methods, making it ideal for retro gaming on modern displays.