SFM isnt rendering properly

[pierogi]

so i just got SFM and just found out how to make a poster i think it doesnt look that bad but when i try to render it it finishes and in the folder i renderd it, it doesnt say i can open it up or open it with anything it doesnt even say it is a png it just says file as file type

[Clown]

are you using the export poster way of rendering