I have put together a short rundown of how the Adobe Photoshop beta plug-in for Microsoft's new photo format performs against current formats. I ran the plug-in through a very basic set of tests. The aim is to get you thinking about the results. Enjoy!
I started off by taking a screenshot of Neowin's header and cropping it in Adobe Photoshop CS2. I then saved it as a Portable Network Graphics (.PNG) file, a Joint Photographic Experts Group (.JPEG/.JPG/JPE) file and finally a HD Photo File Format (.WDP/.HDP) file.
To my surprise, Photoshop presented me with a fairly extensive settings window for my WDP file. The objective of my first test was to keep everything on default settings, so I hit OK, promising myself I'd explore the available options later. Photoshop saved both the .JPEG and the .WDP files as copies, meaning I had to open the files up again.
I headed over to ImageReady, only to have my monitor happily throw out an error. That's beta for you.
Undeterred, I decided Internet Explorer 7 would save the day. It didn't. Neither did Paint.net. No, I did not bother with Microsoft Paint. On the bright side, Vista's Windows Photo Gallery opened all three and naturally, Photoshop did as well. With the former, I used the arrow keys to move between all three images, but I failed to notice any discrepancies. Since this wasn't a very accurate test because the image wasn't very complicated, I decided to move on. I did, however, note the file sizes. At default settings, PNG, JPG and WDP gave file sizes of 38.6KB, 34.4KB and 36.6KB, respectively.
Next, I used a 58.0KB PNG file with an intimidating number of colours and re-saved the file as JPEG and WDP files. Once again, not exactly the best way of comparing the remaining two, but at least the source was constant, and I could compare the file sizes. I used maximum quality settings and found JPG at 2.67MB and WDP at 8.74MB (lossless). That's more than triple the size difference. It is lossless after all. When it comes right down to it though, chances are the spectrum will blind you before you can find a difference. Comparing all three against each other in Windows Photo Gallery gave me nothing the human eye could detect. Nonetheless, it was comforting to see that the option for lossless was present.
I decided it was time to go for the lowest file size possible. Since this is all about Microsoft's format, I went ahead and grabbed one of many Microsoft logos off their support website. The results of this test, wasn't something I was expecting. At the cost of quality, the plug-in allowed me to get a smaller file size than .JPG did, 19.6KB compared to 24.9KB. The quality was in favour of JPG by a lot. And yet, when I saved the file as a PNG, it managed to keep all the aspects of the image, at a mere 5.35KB. That's right, it would seem that PNG is the clear winner. Notice that in the image below, the images are sorted by size.
Finally, I took a JPG of Bill Gates (33.4KB) and continued saving to WDP while setting the quality bar lower and lower, until I reached a smaller size than JPG (29.0KB). This was when the slider was at 0.5. Changing it to 0.4 basically corrupted the image. So tell me, can you see the difference?
In conclusion, it appears that WDP is much more flexible than JPG is: from lossy to lossless. At least when it comes to Photoshop, it has many more options available. That doesn't mean it is necessarily the superior format, but at least it has the edge in the features department. It does still have a long way to go though.
If you happen to have CS2 or CS3 installed, go out and get a copy of the beta plug-in. For any wallpaper creators out there, and I know Neowin has its fair share, it might be a good idea to compare how your work is displayed in Microsoft's format, against every format available. Run it through your own tests, and report back. Comment on whatever you find!
Note: The gallery for this post with all the file types is currently unavailable, mainly due to the fact that it only takes PNGs and JPGs When I get it up again, I will include many more comparison shots.