I want to create a simple wordpress blog site. At the moment I will use a template, but I would like to develop my own afterwards. And I have one concern related to images.

Current template has nice big images and no sidebar, but in my future template I will definitely have a sidebar, which means that I will have to change image dimensions.

My main question - is there a good way to change image dimensions without using css? I wouldn't like to re-create all posts after I change template, because there will be a lot of them.

For example, images at the moment are 900px wide (height is not as important), but in the future template I plan that I will need to change image width to 600px. I would prefer not to do it with css's "max-width".

Perhaps there is a tool that can preserve original image and then re-create them with new dimensions afterwards?

1 Answer 1


Yes, this is trivial in WordPress.

Whenever you upload image WP keeps original file and generates additional sizes from it. Several of the sizes are built–in (see Settings > Media > Image sizes) and any additional ones can be added with add_image_size().

So when you develop your own theme as part of the process you:

  1. Determine image size you need.
  2. Register that image size and use it in the theme.
  3. WP will generate the size from existing originals for you.
  • Thank you for your answer! Wow. I didn't even realize this would be so easy. In which folder are original images kept by the way?
    – Uldis
    Apr 2, 2016 at 11:21
  • wp-content/uploads by default.
    – Rarst
    Apr 2, 2016 at 11:23
  • 1. Hmm, I always thought that those are thumbnails instead of original. Where does wordpress store generated images then? 2. Also, regarding your original reply. Wouldn't it mean that I will have to open each post and re-apply each featured image, in order for new image size to be applied?
    – Uldis
    Apr 2, 2016 at 11:48
  • Originals are stored too, that's what my answer says. Both are stored side by side in uploads. If you want to change existing size there are plenty of tools that can do that (search for regenerate image sizes).
    – Rarst
    Apr 2, 2016 at 12:02

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.