UPDATE (2015/10/26): Unfortunately, the plugin referenced below has been deprecated and is no longer available.
WordPress doesn’t have this option by default but it’s very easy to implement and use…
Process if you don’t have the images uploaded
- Install the “Multiple Galleries” plugin
- Create/open the respective post
- Upload/Insert an Image (icon above the unordered list button)
- Select your images
- Save changes
- Choose your Gallery Settings, select (using checkboxes) the new pictures you just uploaded, and Insert Gallery
Process if your images are already uploaded
If your images are already uploaded you can follow the same steps as above with one exception: you don’t need to upload your pictures 🙂 Simply create your galleries and use the checkboxes to define which pictures you want in each gallery.