OK, by now you’ve probably seen it, reposted across every blog of every stripe imaginable: Lunametric’s Social Media Sizing Cheat Sheet. (Viewable in full below.) Awesome.

For the casual Social Media user and blogger, it may seem a lot of fuss about nothing. Doesn’t Facebook (for example) resize and crop everything anyway? Don’t I get to slide stuff around to crop it the way I want it? Even if I size it myself, won’t they do their own thing with it anyway?

They are all fair questions, and the answer to the first one is simple (yes- it matters!), but the reasons are a bit complex. So permit me, as a blogger on a website currently nearly devoid of decent graphics, to explain why it matters.

First, there is something called generational degradation. Simply put, a copy of a copy of a copy is not as resplendent as the original. But some may protest, this is not a paper photocopy on a 1963 optical Xerox machine, it’s all digital, there are technologies to verify digital copies, right? Checksums and all that?

The issue here is compression. With zillions (sorry, no source for that particular metric) of images to store, a site like Facebook cranks up the volume on image compression before storing your beloved cat pic. The digital image file format JPEG (for example) compression is lossy– meaning that when viewed, while it may look nearly the same, not all the original visual data is present. This matters most when zooming in on an image, but it still matters when compression is cranked up to the max- and FB and friends crank it up high.

The second issue is de-resolution. Your original iPhone 5 (for example) digital photograph is probably a fairly high resolution (say, 3264 x 2448 pixels) with a deep color depth (meaning they had a large palette to choose from, typically 24 bits or 16.7 million colors). When FB resizes that picture for you, choices need to be made about what colors to consolidate and how many edges and details will be retained. All in all they do a pretty good job for you- but they make all the decisions, on a one size fits all basis.

A third issue is preview versus publishing. Facebook allows you to edit each element at a time, and preview the results. But you can only see the final results gestalt of all after you commit each and every one of them. At that point you may find that the mauve background of your Profile Picture just doesn’t jive with the burnt orange graphic of your Cover Photo in quite the way you wanted. Sure, you can mock-up images beforehand, but if you’re going to do that, you might as well go all the way and crop and resize to make sure the rest of the ensemble works, right?

If you really want your page graphics to pop, the first time around, you need to turn off their Autopilot and take back the controls yourself. The first thing you’ll need is a photo editor such as Gimp or (for the spendy) PhotoShop. You might get good results from a simple crop-and-resize capable photo viewer, but the more options you have, the better.

The object here is simple- preserve as much detail and color as possible in getting your pictures down to the destination size and shape. This may require some iteration (iteration is a nice way of saying, be prepared to do it over and over again until you get what you want).

Let’s start with crop. Gimp has a nice area selection feature that fixes the aspect ratio of the selection. No fractional math is required, simply check the box, enter the desired end resolution here, and Gimp will force the selection box to be proportioned identically to your destination size. (Please note this is not a resize yet- it is just using those numbers for the proportions of height to width, thus aspect ratio.) Then crop, and- this is important- save a copy of this intermediate work product (work in progress) to a new filename using a lossless format. The reason is simple, you can always make another crop from the original, but if you bad results from the next steps, you have something to quickly start over with.

Once you’ve cropped out your various pictures into the right proportions, you can proceed with your first draft mockup. This can be as simple as bringing up a Gimp window for each photo and physically arranging them on your desktop, and then mentally ignoring the desktop’s window dressing. While shocking for the purist, this quick and dirty procedure is lightning fast and can catch the obvious errors before investing more time in the crops you have made. Cropped off Kitty’s foot? Failed to crop off Fred’s eyes-rolled-back-in-head photobomb? A quick do-over and then move on.

The next steps are the resize and second draft mockup. Resize each pic to the actual target size (sometimes a little different than final display size, such as FB’s Profile Picture which ends up smaller than their minimum required upload size). Then put them all together in something you’re familiar with, like a word processor or an HTML editor. This is getting really close to what you will see on the target site.

Now comes the iteration part. Try exporting the candidate photos to JPEG format at a high compression level, say 97%. Not good? Reduce the color depth in your raw format original and try again, adjust the colors and retry until it comes out looking pretty good in the JPEG. Then save to a lossless format that the site accepts, realizing it will get converted to JPEG in much the same manner you were just doing. For graphics, Facebook accepts .png , and for photos use .tiff.

If you’re really a perfectionist, or your boss is… you can do a third draft. This is where it gets a little tricky. Do the final draft using the highly compressed JPEG pics, realizing that you won’t be uploading them, but rather the .tiff or .png source files they come from.

Finally, when you’re ready to go, upload the cropped, resized and palette-reduced source images (the .tiff and .png not the .jpeg) and admire your handiwork on the social media site. The object here is to bring your work so close to the final result that the host site can’t mess it up too much. But, they might anyway, so be prepared for the occasional retry. You may need to increase the color depth (by going back to those unresized source crops in Step 1) to give them more to throw away and end up with a usable result. Now, you can sit back and admire the product of your obsessive compulsive control freakish efforts.

So, without further ado, here it is: