bulk renaming multiple file
There are couple of way to rename multiple files.
example we have files
image0001.png
image0002.png
image0003.png
...
And we would like to rename it to
0001.png
0002.png
0003.png
...

with for loop

this works with linux and mac without installing anything
for f in *.png; do mv "$f" "${f#image}"; done

With ZSH

This is my favorite way since I'm using ZSH and oh-my-zsh. Check it now, it's awesome
$ autoload zmv
zmv 'image(*.png)' '$1'
or let zsh automatically define $1, $2 etc
zmv -w 'image*.png' '$1.png'

Using your editor

for more complex operation, sometimes it easier to rename the file on your editor.
there is qmv from renameutils
$ qmv *.png
it will open editor with 2 columns, you can edit the right size rename that file