Canvas can be a beast of its own. My opinion doesn't mean squat but I would seriously reconsider spending money on the beach foot print image. It needs a boost in exposure to work on canvas and it lacks appeal. Good idea, not good execution. You need to show a longer trail of foot prints.
Of the images posted, #2 probably has the best shot at selling.
Some of the inexpensive 'canvas' is actually textured plastic.
There there is the issue of how the image is put on the media. If it's an inkjet process, are the inks that will be used dyes or pigments?
Dyes fade quicker and need an over-coating. Pigments last longer and don't need an over-coating.