If you have a ton of images that need resizing, you can do it all with the imagemagick package:cd /home/user/imagesmkdir resized_imagescp /home/user/images/* /home/user/images/resized_images
Now that you have a copy of the files in resized_images, time to resize them all:
mogrify -resize 800 *.jpg
If you have many large images or photos and you want send them via email or publish into your website, you will need to resize them first. You can do the batch resize using this free and powerful VSO Image Resizer. With this software, you can resize images, convert and rename multiple images easily.