Think Buyers. Most don't want to process their purchased images. That's one reason the jpg images are offered in several sizes. The savvy user could buy the largest size and change the size to fit but many do not want to do even that.
DT converts all images to TIFF so why bother doing it yourself? In fact, you cannot upload a TIFF.
Not every buyer is familiar with how to process a Raw image or have the software to do that so don't want to buy them. It's all about the Buyer. It's up to you if you want to upload your other formats, you don't make any more money and many consider their Raw images their "negatives" and would never sell them.
Processing a Raw image, setting the right levels, isolating the object and retouching the model etc...these are very different specialties that belongs to photographers. Many designers don't have the ability (and they do not have to...) to process a photo, in the way a photographer can. Also, a photographer cannot design a brochure or web site, in the way a designer can. So, everyone does his job :)
Starting with a raw file and degrading it to jpeg is a step-back, this is a scientific truth, for sure. But the size, compatibility and usefullness of a .jpeg is more important than the quality of a Tiff or raw file.
You would be amazed sometimes to see the difference between the original RAW image and the final jpeg. Processing the images is part of a photographer's job and can have a major influence on visual impact.
Besides that and many other technical aspects, there are major legal issues that can appear when accepting RAW files: how does one remove copyrighted material from a RAW file before submission?
@Red - I do not chat with Buyer directly, but it seems hard to believe these days!
@Dewers - There seems to be allot of debate over that, but the same arguments could be said of JPEGs...
@Parkinsonsniper - Why not convert your files to DNG with all the corrections?
I used to convert all my CR2 right to DNG, but found that with older machines, a single change to the file would cause the whole file to be back-up instead of a simple XMP file (kb sized). Basically, quicker back-ups.
As for quality, when one Uploads a JPEG to DT, and then is re-res-ed to 'other' sizes, there is going to be some degradation of the file, plain and simple. So why NOT start with a HiRes (RAW/DNG/TIFF) and work down from there?
As for file size... What is a 50+MB file these days... When you Print your own work at a Print shop like AdoramaPix, what size are they?
@Costa007 - Been a Photoshop user since version 1.0, and work in digital media ever since... Most of my work is HDR... Tone-Mapping and Masking are OLD friends!
@Synthetic - Might want to Check that...
My point is, why not Upload the Highest Quality first, and make the derivatives from there?
In terms of stealing, you have placed a digital file in a public realm. Is it fair NO. http://petapixel.com/2013/09/24/philippines-student-wins-contest-stolen-photo/
and when you see Google doing this - http://petapixel.com/2013/09/26/google-unveils-improved-raw-jpeg-conversion-supports-70-cameras/
it has to make you wonder why DT seems behind the times...
Just my two cents...
I shoot mostly camera RAW, with HDR in mind. All of my fi...