Simplest way to resize a folder filled with pixel art

Question

I'm trying to compile a nice website/portfolio for internships etc, and I have a folder filled with pixel art I've done (100's of images, not feasible to do them one at a time except if absolutely necessary).

Unfortunately, it's all a little small (32x32 and the like) and the website service I'm using, Squarespace, displays them at actual size. I really want to make all of my art 2x as big (or perhaps 4x as big) without losing the pixel quality (I don't want any blur or anything like that). I've looked in a lot of places and I can only find vague references to unwieldy command line programs that I can't seem to figure out or links to webtools that take several seconds per image to do.

I would much appreciate a step-by-step guide (or link to one) on how to do this in the simplest way possible, for free or very cheap. Thank you!

Answer 1

You could use imagick's convert with "point" filter Just run loop over all your files like so:

for inputfile in *;
do
convert "$inputfile" -filter Point -resize x256 +antialias "$inputfile".scaled.png;
done

Replace x256 with desired height and change extension as you like.

…this would be for Linuxshell - but there's a Windows version, too. See ImageMagick-Homepage

Answer 2

https://redketchup.io/bulk-image-resizer

After a wild goose chase, I've found this hidden gem here that's extremely helpful. It's able to batch resize or pad the images with nearest-neighbor scaling algorithm.

Usually my personal settings while working with it are like this:

Upscaling

Resize: Percentage
Scale Percentage: 800
Resampling: Nearest Neighbor
Color Depth: 32-bit (important)

Padding

Resize: Padding
Dimensions: 300x300

However, it doesn't seem to make optimizations. Generally I'd pass the zip-extracted image folder through GIMP with the "Save ALL" script to achieve an optimized spritesheet folder that is 2.5x smaller.

Answer 3

Photoshop batch action with Nearest Neighbor resizing.

Set up an action, create a droplet...

Drop the folder on the droplet and let Photoshop do it's thing.

I do this monthly for a client of mine who supplies several images that all require the same 6 steps in Photoshop to make them usable.

Here's a link to a tutorial I just found. It may help. I didn't go through it extensively.