#!/bin/bash

echo -n "Please write an output filename (example: output.tar.gz): " 
read filename

echo -n "Please write the prefix for the file to be zipped (optional): "
read prefix

tar -cvf $filename "${prefix}*.jpg" "${prefix}*.png"
rm "${prefix}*.jpg" "${prefix}*.png"
echo "tar successfully filename is " >> $filename

#!/bin/bash

echo -n "Please write an output filename (example: output.tar.gz): " 
read filename
tar -cvf $filename *.jpg *.png
rm *.jpg *.png
echo "tar successfully filename is " >> $filename

--- 
+++ 
@@ -2,6 +2,10 @@
 
 echo -n "Please write an output filename (example: output.tar.gz): " 
 read filename
-tar -cvf $filename *.jpg *.png
-rm *.jpg *.png
+
+echo -n "Please write the prefix for the file to be zipped (optional): "
+read prefix
+
+tar -cvf $filename "${prefix}*.jpg" "${prefix}*.png"
+rm "${prefix}*.jpg" "${prefix}*.png"
 echo "tar successfully filename is " >> $filename
Add prefix to make tar