Converting multiple images as a single PDF document can be useful when preparing reports, or for submitting documentation and so on.
Image To PDF is a Windows freeware that does that and is easy to use.
Download and install it from here.
Once installed and launched, the main interface is self explanatory. Add images or folders that contain images which need to be converted to PDF files by choosing either Add image files or Add folder.
Next, select how the images will be displayed in the PDF document from the drop-down menu Position of image.
Select the paper size for the output PDF file using Paper size. This can be useful when printing images for different purposes.
Finally, choose the compression type.
Click Start Convert. Select an output folder or path where the images will be stored as a single PDF document.
The selected images will now be processed and the PDF file will be generated in the output folder/path.
(There is another similar free tool which does this, more about it here).