added gzip func to pngizer

pngizer.sh

@@ -1,6 +1,6 @@
 #!/bin/sh
 # PNGizer: convert any file into PNG image and back
-# Depends on mktemp, tar, ImageMagick and pngcrush
+# Depends on mktemp, tar, gzip, ImageMagick and pngcrush
 # Created by Luxferre in 2026, released into public domain
 
 # Convert any raw data file to PNG
@@ -43,7 +43,7 @@ pngize() {
   [ -z "$2" ] && ofile="$1.png"
   temp_arch="$(mktemp)"
   # containerize the input 
-  tar cf $temp_arch "$1"
+  GZIP=-9 tar czvf $temp_arch "$1"
   # run the conversion
   pngize_raw $temp_arch $ofile
   rm -f $temp_arch
@@ -55,7 +55,7 @@ pngize() {
 unpngize() {
   temp_arch="$(mktemp)"
   unpngize_raw "$1" $temp_arch
-  tar xf $temp_arch
+  gzip -dcq $temp_arch | tar xvf -
   rm -f $temp_arch
 }