Sharing images can be complicated. One image may be fine, but if you've got a pile of pictures, you don't necessarily want to have to attach half a dozen PNG files to an email or upload a stack of JPGs to a server somewhere. One way to avoid all that is to combine your images into a PDF file. Everybody's got Adobe Reader or some other PDF reader app, and it's always going to be easier to deal with one PDF file that a dozen individual image files.
Swift PDF takes your individual image files and combines them into a single PDF document. Drag and drop your images into this tool, and then drag them around to re-order them in your doc. You can choose margins and layout for your document, including the size and orientation of the paper. In addition, you can customize margins for individual images, and decide to stretch images to fill a space. Add meta info—title, subject, author, keywords—and you're good to go.
Swift PDF is a free download. It's a Windows application and runs under Windows 95 / WinNT and later.