I have some drawings I made with an Intuos tablet. All of these drawings are 25×35 or so. The color of each pixel was very carefully selected. They're kind of like 'miniatures.'
I need to resize these. But I ran into problems. The images get dithered, and if I make them huge, blurred.
Here is the image at normal size. It happens to be dithered, but this is not visible.
I used the following two imagemagic commands, but they both produced blurring:
convert -resize 400% image.xcf image-2.jpg
convert -adaptive-resize 400% image.xcf image-2.jpg
Best Answer
There are many more resize options in imagemagick.
-scale
looks like what you need.Also, do not use JPEG for pixel-perfect "miniatures"; use PNG instead (or if impossible, GIF). JPEG is designed for photos and uses lossy compression, resulting in distortion clearly noticeable after scaling your provided JPEG sample.
This article on image scaling might be interesting.