Once you've installed Picasa and the program has catalogued all of your photos, you can start gathering the pictures you want to include in your website gallery. To get started, create a new album in your My Pictures folder, and call it 'Gallery' or 'Website pics' or something else that you can remember. If your photos are of a specific event or location you can add this and a text description to the album. Once it is created you can begin to drag and drop the photos that you want to publish into this folder. Don't worry about resizing them, but you might want to edit the file names to something descriptive. Picasa will display the photo using the file name, and the title "DSC001024" doesn't tell you much about the picture.
Once you've got a Picasa folder filled with the pictures you want to publish, click on the Folder menu and select Export as HTML Page. HTML (which stands for Hyper-Text Markup Language) is the code that is used to write websites. You web browser program (such as Internet Explorer, Safari or Firefox) reads this code and displays it as the website you see. Professional web designers will often create websites by writing this code directly using a text editor, but in this case Picasa writes the code for you and puts it all into a format that can be uploaded directly to the Internet. It also automatically re-sizes your pictures for faster loading and to save on storage space, which is handy since our free webspace is so small. For the best compromise between size and quality, I've chosen to re-size mine to 800 pixels, which produces image files for uploading that are between 60kb and 150kb, so our 55MB will be enough for at least 500 pictures. If you have more photos than that then re-sizeing to 640 pixels might be a better idea. You also need to specify a folder into which the gallery contents will be placed. Put it on your desktop or in your My Documents folder.
You'll also need to select a style and colour scheme for your gallery page, but this is merely a matter of personal preference. I've chosen a black two-page layout because I happen to like it.
Once you've made your selection, click Finish and the program will do its stuff. It's very quick, creating a web gallery from 50-60 photos in just a few seconds. If you have a look in the folder you told it to write to, you'll see it has created several new folders and a lot of files and HTM documents. If you want to see what your gallery will look like in a web browser, double-click on the file named "Index".