I have had a Raspberry PI Zero fitted with a camera module installed on a frame which attaches to a window for some time now. It has installed on it Motion which has been configured to take snapshots when there is movement. It can also be used tp stream video and runs fine on the Raspberry PI Zero. The format of the pictures are not ideal for creating animated GIFS as Motion by default sets the files in a date format naming convention as it is primarly to be used for security camera purposes while if you want to use a tool such as FFMPEG to create a file you need a padded numeric sequence so the tool can created a GIF in number format.

I have an empty sample of what I produced below minus pictures of the kids

I was able with some tweaking using Windows Explorer and alot of manual changes to alter the file names but I would recommend using motion.conf to specify the file name rather than going manual if animated GIFS of your kids in the back garden are what you want. Also the file format of the files produced by Motion are PNG and I do not think this can be changed so that is something you will need to change as well.