Yesterday, we saw how to set the default screenshot format on your Mac to JPEG instead of PNG, in order to make your screenshots more universally usable. You can’t change the default screenshot file type on iOS, so today we’re going to look at the next best option — converting PNG to JPEG as easily and quickly as possible.

By default, any screenshots you take on your Mac, iPad or iPhone get saved as PNG files. That’s great, because PNG files are pixel-perfect, and they support transparency (for those neat floating-window shadows).

But they’re not JPEGs, which means they’re not universally supported. Luckily, you can easily make JPEG screenshots the default, at least on the Mac.

Here’s a slightly obscure tip that’s worth sharing becasue it could literally save you from a lost photo library. If you use Lightroom, Adobe has a “secret” script you can download that extracts the JPG images from your previews. Why would you want to do this? Say you lose the hard drive with all your original RAW photos on it, or you just get drunk one night and wake up in the morning to find you deleted your Lightroom folder.

This script will rescue you.

Back up your photos. Always shoot in RAW. After a while all the good advice starts to sound like the adults speaking in Charlie Brown cartoons. Wah-wah-wah-wahwahwah.

Especially now iCloud manages our backups and our iPhones only shoot JPGs.

But one piece of advice is still worth listening to: “always rotate JPGs losslessly.” What?

Taking photos is a ton of fun, especially with our nearly ubiquitous iPhones or iPads. I can’t tell you how many people I’ve seen in the last month or so snapping pictures with the big tablet device. Looks silly, but makes sense.

How do you get them to your Mac, though? You could email them, one at a time, or you can connect the device to the Mac and grab them via iPhoto. These days, you can even use PhotoStream in iPhoto to see the latest photos you’ve taken on any PhotoStream-enabled iOS device. Todays tip is even faster than that.

VSCO’s Cam is a film emulation app for the iPhone and iPad (pixel doubled). It is also one of the new generation of “serious” iPhone camera apps which capture uncompressed JPG files before applying filters, for a much higher quality end product.

645 Pro bills itself as an app which will turn your iPhone into a DSLR. At first glance, it seems like this has been achieved by mimicking the buttons and LCD panel of a modern SLR, and to an extent that’s true. But the real meat here is under the hood: 645 Pro shoots uncompressed JPEGs and TIFFs, and gives the closest that we’re likely to see to RAW images from the iPhone’s camera.

Have you ever wanted to change the default screenshot format in Mac OS X? The default PNG files can end up being huge, especially with higher resolution displays. In this video, I’ll show you how to change the format to anything you’d like, even a PDF.