How to Batch Convert Images with ImageMagick

Step 2:
Right-click in your folder with the images while holding Shift. In your menu, you will see “Open command window here”.

Step 3:
To batch resize all the images in the folder, type in the following command:
convert -resize 100×100 *png filename.png

What this will do is resize all .png files in the folder and it will give them the filename you specified + 1 number. The size will be 100×100. Simply edit that data to suit your needs.
See the image above. The files called diamond_test-*.png are 100×100, the files below it are the original sizes.

To resize only one image, use the following command:
convert -resize 100×100 filename.png filename_new.png

Again, what this will do is resize your file called filename.png to 100×100 pixels and it will call it filename_new.png.

It pretty simple and very useful. Good luck!

I needed a tool to batch resize transparent images, so I started searching around. I found ImageMagick which does the trick perfectly.
Here is a simple guide on how to (batch) convert images using ImageMagick

Step 1:
Download & install ImageMagick.