I'm aware this might be an "opinionated" question, but as I'm desperately looking for feedback on my opensource project rawson.js, I'm asking it here:

do you see a use case for a lightweight, browser-based raw previewer?

by "browser-based" I mean only relying on client-side web technologies (javascript), a "raw previewer" only extracts and shows the embedded jpeg preview image of the raw file which is magnitudes faster than decoding the entire raw file.

use cases I was thinking of:

  • quickly post a raw photo to a social network or photosharing service directly from your browser without having to start lightroom

  • safely open raw image files on guest computers (nothing is stored on disk, the browser cache is emptied automatically in anonymous mode)

  • a cross-platform raw previewer (picasa dropped linux support, so there is no common raw previewer on all OSes)

[UPDATE]: thanks for your feedback, here is the another important use case:

  • integration into HTML5 Uploaders: instead of manually converting a raw to jpeg for upload in a html form, rawson.js could do this automatically to you. (you choose a raw file, it gets converted to jpeg before upload, only the jpeg data is uploaded then)

but I'm curious about your suggestions...

  • \$\begingroup\$ Online free RAW converter (rather than "viewer" but close \$\endgroup\$ Aug 28, 2012 at 19:30
  • \$\begingroup\$ I would have no interest at all in a browser/Javascript based raw viewer. The ability to view raw files is built into Mac OS and that is all I need, I would not want to open a web browser to do that. \$\endgroup\$ Aug 28, 2012 at 20:30
  • 2
    \$\begingroup\$ Since this is built in to Windows and OSX, simply viewing the card with the OS file viewer is sufficient, and frankly even easier. \$\endgroup\$
    – cmason
    Aug 28, 2012 at 20:52
  • \$\begingroup\$ @cmason - built into windows? Really? My win 7 computer doesn't let me preview RAW, I have to open them in PS or LR to preview. \$\endgroup\$
    – dpollitt
    Aug 29, 2012 at 1:12
  • 1
    \$\begingroup\$ You are missing the codec. The ability to view images as decoded by an installable codec is built into the OS. There is no way it will understand proprietary RAW formats in general. \$\endgroup\$
    – Itai
    Aug 29, 2012 at 2:23

4 Answers 4


I could consider use for this tool, since many times I travel with a mini laptop, capable of only 1024x600 resolution, so canon applicatin won't even run the installer. During this trips, (when I go back to the hotel for a rest) I'd like to review my shoots and discard the unrecoverable ones or the ones that are clearly bad enough (not good enough to keep). This is a task much more comfortably performed on a 10 inch screen rather than on a 3 inch.

The proposed application could allow me to review my shots while charging my camera's batteries.

Also, I guess this web client could run in several browsers, including those on tablets, which are even more comfortable to use, lets say, in bed after a whole day hiking with a backpack full of equipment.

I recently has another ocassion for use of similar technology: I had just shoot an event, and I was asked to project the pictures right away for the attendants to enjoy while they were having a brunch. Awfully I realized that I had forgotten to press "OK" when I selected "RAW+JPG", so the shots were only RAW. I could not project the pictures because when the computer was conected to the projectors, the resolution was unavoidably set to 640x480, not enough for the Canon apps to run. The proposed raw previewer could have saved my neck, specially if it had a "slideshow" mode...


This is an opinion question, so here is my opinion:

No value. If you shoot jpeg, you are likely to be willing to post it to social networks straight from the camera. But folks who shoot raw want to adjust it in post processing. That is why you use raw.

A quick and dirty display so you can post to Facebook defeats the purpose in shooting raw.


I'd say there is a case. There are tools for raw but 90% of the time I don't need these tools, I just need to see the image and I don't want to find out the app to display this image. So, an online solution works. If I am using RAW all the time, than I install it. So there is a market for people who doesn't need raw often.


In my opinion there is a current trend that more and more applications are moving into the browser/cloud. Thanks to the always improving javascript interpreters it is possible to create and execute more complex client-side javascript. Of course most browser-based solutions are not nearly as complete as the native applications, but the fact that they work on every computer (if there is a recent browser installed) can compensate for some missing features. Maybe this is only a short phase and in a couple of years there is a movement back from browser/javascript to native applications, but maybe in a couple of years most “native” applications will be javascript-based running in its own browser instance? So I think your RAW Previewer is useful and I think your second and third use cases are very strong. I would even think a full-fledged browser-based RAW Converter would be interesting, but I could imagine performance issues and to develop/port this in javascript would be difficult. But on the other hand there exists the Native Client for Chrome and Active X for IE, where you could use the unaltered (or slightly adapted) dcraw.

Examples of existing browser-based applications:


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