Not entirely clear because some key details aren't clear in the photo because it's dark and small. However, one diagnostic is the shape of the antennae. Butterflies typically have a knob-like bulge at the end, while moths usually have feathery antennae. I can't clearly see which in this photo. Another diagnostic--which has exceptions--is that many butterflies at rest hold their wings up, whereas many moths hold them either horizontally, as in your photo, or folded back over their bodies. Since you have the fuil-size photo, see whether the antennae are clear in the full-sized image.
Here's a butterfly image that shows the bulb at the end of the antennae. I have only a few photos of moths, and can't easily find them.
Clicking on the image gives an image that is only 700 x 433 px, which is still pretty small. Also, the antennae aren't in focus. I tried lightening the image in photoshop and then blowing it up larger, but it's still not clear what the antennae look like. I would have guessed a moth given the wing position and the coloration of the thorax, but it would be nice to have the antennae as a check.
Perhaps Geoff will weigh in. He's very knowledgeable about entomology.
Looking at it's delta wing shape marks this out as being a moth to me. I think that this is a species of carpet moth but there are a lot of different types so can't be 100% specific on which one.