Is there a way to avoid using add_image_size? Best way to manage images

Question

Currently if you have a theme that use add_image_size for let say 6 different image size you will have 6 different thumbnail created that will maybe never be used.

With the current version of WordPress what is the best way to make a theme that use 6 or more image size.

What about the wp_get_attachment_image function, if you use an array instead of a thumbnail size, does the image thumbnail get generated on the fly, how does this work?

I would like to use more than 8 different thumbnail sizes without having a lot of un-needed thumbnail in my ftp wp-content folder.

Any advice is welcome

Answer 1

When a theme or plugin adds an image size to the list of thumbnails, they will be added to the global $_wp_additional_image_sizes array. This means that every time you upload an image, any additional image sizes will be generated right after the upload is completed.

The answer to your second question is no. WordPress does not generate thumbnails on the fly. They will all be generated after each upload.

If you are going to add a dozen of image sizes and your blog has a lot of images, I suggest you use a plugin that allows you to organize your upload library, or you can use the code from this answer of mine to do it yourself.