I've gotten a comic that is a standard folder of .jpg pictures and was wondering if there is a convenient way to pile them into a .cbz file for easier reading.
...then use some compression software (like WinZip, standard on PCs)...
Actually, the ability to make a zip file is built right into Windows without needing Winzip or anything else. If you open up the folder that contains the files, highlight the first file, hold the shift key and click on the last file. This will select all the files you want in the cbz. Then, right click on the highlighted group and select "Send to...", and from this expanded menu, pick "compressed file". You will get a zip file named after the first file name in the group. Right click on this file 'first file name.zip' and select 'Rename' and rename the file to the comic book name with a CBZ extension, rather than a ZIP extension. You will get a warning from Windows about the potential disasters of renaming file extensions. Don't worry about it.
Winzip does make it a little easier, and is a free download, but it is essentially the same process without it.