Print on glossy film paper, or head to your local copy center and get a bit of help. My jar was six inches in height, so I created a horizontal image to roll into the jar. Trim around the picture ...

Then print it out, fill the jar with tinted water (make that tint acid-free to maintain the print in a good enough state for a long time), and put the print inside.

Simply edit together two side profiles and a portrait of a head, print and laminate it to ensure preservation, then place in a large jar filled with water dyed with food coloring. With that ...