Toddlers are learning so many things: shapes, colors, how to use glue, and, if they're old enough, even how to use scissors. As often as possible when it comes to art, I like to give S the supplies to create and then just sit back and watch what she comes up with. A younger toddler may not be ready for scissors, and instead may experiment with glue and making a collage out of shapes. Because squeezing a glue bottle can be a bit challenging and often frustrating, I like to give toddlers a shallow dish with some glue and a paintbrush instead. Glue sticks are another less frustrating alternative to glue bottles. I provided precut shapes of different sizes and colors. I happened to use foam sheets on this occasion, but construction paper would work just as well.
Older children who are working on scissor skills can snip and change the shapes as they please. S had fun changing a circle into a fish, for example. Once her shapes were where she wanted them, she used a black marker to add some details.
Because she is always creating, we can't possibly keep or store all of her art. Instead, I always grab a digital photo of the finished pieces. One of my favorite things to do with the photos is use a photo editing software (both Picasa and PicMonkey have free options where you can do this) to add text to the photo. S always has very elaborate explanations for her art, so she dictates the story or tells me what each item is. Here is her finished shape art, complete with explanations for each piece.