Use image upscaling software or AI image enhancers
Increase canvas size in an image editor
Resample the image to a higher pixel dimension
Start from the original high-resolution file if available
Scan printed images at a higher DPI
Export or save using a higher quality setting
Use vector graphics instead of raster when possible
Reduce noise and sharpen after upscaling
Avoid enlarging low-resolution images too much
Use professional editing tools for better results