A flashlight projects a solid, straight beam of light. You can use this type of light to make your own small projector. This type of projector would be designed to work with small slides, be they regular photographic slides or ones you make yourself. You need to change the flashlight's beam in two ways to make this work. You need to distil the light before it hits the slide, and you need a means of magnifying the image.
Cover the lens and front end of the flashlight in tissue paper, securing the paper with rubber bands.
Cut two pieces of cardboard into U shapes with square corners, making them approximately the same size as the flashlight. Make one piece's opening wide enough to hold a slide and the other's opening slightly smaller.
Glue the two cardboard pieces together back to back, forming a small frame to hold slides in. Tape this frame, with the thicker piece on the outside, in front of the flashlight's covered front end.
Insert a slide into the frame so it is held in place directly in front of the flashlight.
Point the flashlight at a blank wall and place a magnifying glass or fresnel lens in front of the light. Turn on the light with it shining though the lens to project the image; adjust the lens's position to focus it.
You can design your own slides by cutting out small pieces of transparent plastic sheeting and drawing on the pieces with coloured markers.