How to create a photo gallery in a WordPress site?
Create new page or open a page for editing. There is no difference creating a gallery in a post or a page.
When you are editing the page just Click the Add Media button.
A new window will open, there click on create gallery link.
Select photos from you computer. To add photos from your hard drive, you can drag and drop your files into the box that appears, or click Select Files to choose a picture from your computer to upload. WordPress will create thumbnails automatically.
After the images have finished uploading, click the button insert a new gallery
You can choose how many column you prefer in a row. You can also click on each image to edit its title, caption, alternate text, and description. Be aware that only the caption will be displayed for the slideshow gallery type.
Then click the button create a new gallery