Of course if you can see all the photos on a single page in their full-sized version, Using your browser’s File, Save As and selecting Web Page, Complete or words to that effect (depending on browser) will save them all in a floder attached to the hatl file so the saved page can be viewed on your desktop without an Internet connection.

If the glalery uses small thumbnails and links, you need a special tool like WinWSD Web Site downloader which will spider the site and download all linked pages as well as the main page. But some dynamically generated gallaries are deliberately designed to prevent spidering. There, the only way sadly is to hand click to each image and save them individually.

Happy click-and-save.

Yes a program called Extreme Picture Finder from Exisoft—they have a free and a paid version