The lamp on the cover reminds me of the Tiffany lamps that were and are so popular, and Tiffany anything used to be a status symbol as they were expensive. If you were able to have those, you were fairly well off. Further though, light itself has a lot of symbology.
Light originates from the sun, and there is a meditation to gain more energy by visualizing yourself being filled with light coming from the sun. Reiki practitioners often channel Reiki or original ki from Source (more familiar as God to Christians, but the ways this is seen by various cultures is a whole book in its own right) to themselves and those they are doing healing for. It also stands for enlightenment to some people. You see it this way in the Hermit card of Tarot, in the lantern being carried by the wizened old man at the top of the mountain. Light from that lamp or lantern is knowledge. For the child, the light from the lamp or nightlight chases away the Boogey Man, monsters under the bed, and the Thing in the closet. The light from the lamp makes it much easier to deal with any danger once it can be seen for what it is. Quite literally, a lamp is the Light in the Darkness dispelling ignorance and fear, and in some places can equate on a smaller scale to the Lighthouse symbolically.
For myself a lamp also represents hope, for the reasons above but also because lanterns, lamps, and lighthouses remind me of my father. I lost my father to cancer on December 1st of 2008, and lighthouses were something that we loved to go visit when I was a child. A favorite movie (that we did not watch as often as I grew older) was Pete's Dragon which also featured a lighthouse and its importance. When he died I was lost and devastated, to the point that for a month what my mother and I survived on was mostly Ensures since neither of us was coping well enough to even cook.
Then the Lighthouses started cropping up as we got more and more of the final affairs taken care of. We found his urns in an antique shop called Hidden Treasures, and I found what I was going to wear for his funeral in a shop called... the Lighthouse...
Thus for me the lamp on the cover resonated greatly, and I considered it an even better choice after reading the three short stories through and seeing how the lamp matched the content.
One final set of symbols that equate with the lamp that I can think of are flashlights (portable torches) and the old fashioned torch. What other symbols can you think of?
Why did I make such a long post on lamps and the associated meanings? Symbols are very important when writing, and when being able to consider possible meanings attached to things, this can add another layer to writing.