imagemagick command line convert script using Linux terminal

Question

I create PNG image files with GIMP and want to make several icons from that PNG image of different, size and file names.

I wish to 'batch' convert with ImageMagick or something similar. And have the naming convention and size requirements read from a text file possibly because I also want to create another separate image using GIMP and have that re-sized multiple times with different file names on each also.

Edit

One image file needs to get converted into THIS:

  Icon.png  
  Icon@2x.png  
  Icon-72.png  
  Icon-72@2x.png  

the file dimensions to be THIS:

  57x57  
  114x114  
  72x72  
  144x144  

$ convert image.png -resize 57x57 Icon.png  
$ convert image.png -resize 114x114 Icon@2x.png  
# ...etc  

Answer 1

so if there's a text file storing the map "file name -> picture size" just in two columns, then you should be able to iterate through lines eg like this:

cat map.txt | while read line; do
  file=$(echo $line | awk '{print $1}')
  size=$(echo $line | awk '{print $2}')

  newfile=${file%.png}-new.png

  convert $file -resize $size $newfile
done

Answer 2

It's kind of hard to guess what you mean, but suppose params.txt looks like this:

-resize 64x64

Then you could do this:

#!/bin/bash
params=$(cat params.txt)
for f in *.png
do
   newname=${f%.png}_new.png
   echo convert "$f" $params "${newname}"
done