Is there any simple way to export PSD file into PNG images without Photoshop?

I make web apps, mostly backend, but sometimes frontend as well, and our designer sends us only PSD files, so we export what we want and how we want. However, Adobe Photoshop is not the cheapest program and although it has one month free trial, I usually need it about once a month and that means downloading and installing PS almost every time I need to export anything and that kind of sucks. Buying PS just for exporting sucks too.

Is there any easier way to get the layers from PSD as PNGs without Photoshop, so I don't have to steal the software or go crazy?