Is there even an alternative?
its still one of the most light/fast image viewers that offers the most functionality at the same time. I've been using it since 2002. truly a well programmed piece of software
Irfanview would be perfect if its save function could preserve transparency properly.
And if the save function's filename autocomplete didn't wrestle you for control on Win10.
And if its 64-bit version could read Unicode filenames.
And if its icon weren't roadkill.
Other than that, though, I fucking love it and couldn't live without it.