Ask HN: image scaling on the fly | Hacker News Reader

Ask HN: image scaling on the fly

9 pointsErlend26 comments

Hi,

I've built some mobile sites & apps the last few years and rescaling images keeps popping up.

Ideally I would want something like this:

http://scal.er/w40-a1:1/http://path/to/image

this would generate a square thumb, 40x40.

I would be willing to pay for such a service.

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Why not use ImageMagick?

I have used it to create thumbnails for a demo website and they looked OK. Does it have any performance/ aliasing/ whatever issues I'm not aware of?

ImageMagick is gold for this sort of thing. I'm actually working with it as I type :)

I've used ImageMagick and it works great. Though I think many average developers who don't tinker with servers would have a harder time picking it up.

Was there a question being asked here? If you are looking for a programmer-for-hire, there are freelance sites for that sort of thing. This isn't even an hard/interesting problem, and anyone who could "build a mobile site/app" should be able to code up this trivial service in minutes.

Sorry, I wasn't clear enough earlier.

I have used imagemagick/GD previusly, but there are some hassle involved in setting up this for each project/client (cron job for cleaning up thumbs, space considerations, not all ISP I use for clients have GD installed etc)

I agree that writing an ad-hoc image scaler is simle.

However, writing a quality general one that handles different formats, image quality, aspect ratio, smart cropping etc..is not trivial.

Righty-o. Didn't mean to sound annoyed, but there has been a bit more Craigslist-y trolling-for-programmers-for-hire than usual lately it seems, and that kinda stuff needs some trouncing IMHO. :)

Also, you are going to be limited to the tools for processing images that are out there for the most part, which sadly means ImageMagick and/or GD. But not SO sadly, as both of those (while annoying to deploy, granted...) have decent bindings to everything, support a pretty good selection of images types, and have params for controlling the aspects you mentioned (except maybe smart cropping).

Everything else is arithmetic and designing a clean, RESTful URL scheme for invoking it. I guess I meant trivial in the sense that all these things are solved problems or only require a bit of time/cleverness.

I built one of these a few years ago using PHP/GD, and it performed admirably (and did everything except smart cropping in your aforementioned list...)

So, feel free to hit me up if you get stuck on any specifics. Been there done that, and can commisserate if nothing else. ;)

Thanks for that, I'll let you know if I get stuck.

At work I developed a wsgi script that use Python Imaging Library to resize images on demand. You can see it in action here:

http://dyn4.media.forbiddenplanet.com/products/2148557.jpg.s... http://dyn4.media.forbiddenplanet.com/products/2148557.jpg.s...

Basically, if you chop off the dyn4 sub-subdomain and everything after .jpg you can see the original unmodified image. You can also change the extension at the end to change the format of the image (jpg,png or gif). We cache the files to /tmp which we periodically clear out. Whilst it might be more efficient of going down the route of pre-generating all the images we'll need, it's very convenient being able to do it on the fly and to be honest for a site of our size (225,000 visits/month) it's barely a spec on the CPU load of our media server.

There's also an apache module that uses ImageMagick to do something similar:

http://github.com/beetlebugorg/mod_dims

I have to be honest though, I prefer the API for my version and it gives the files a meaningful name in the /tmp folder as well as the user's internet history.

Unfortunately my version isn't open source (yet?) and the code is a bit of a mess, but it's something we have considered opening up.

There is http://imagejuicer.com/, that seems to do what you want.

Has anyone here used Image Juicer?

It looks interesting but I found the documentation page to be pretty lacking. The simple example they show just allows you to pass a height and width parameter, but the home page says you can do cropping, watermarking, etc.

From their site:

You can pass other info in the outputs hashes, like labels, your own ids, or whatever. That extra info will be passed back to you in the response JSON.

So I assume it is a case of emailing them and asking for an exhaustive list of what can be passed to their api, the documentation definitely needs work.

Thanks, but looks like its mainly for background jobs and not built to serve images on the fly.

This looks like the answer.

I'm currently wrapping up work on an image processing module with a client. If you want I could build a dedicated service for you.

If you are running your own site, and using nginx, there's an image processing module for it that is a match for your requirement: http://wiki.nginx.org/NginxHttpImageFilterModule

Thanks for that, but Im looking for a "pay as you go" service.

I wrote a HTML=>PNG service last week (http://htmltoimage.tenprinthello.com), so it's just a hop to an image resizer.

If you want one developed, please contact me, my email is on my blog @ http://www.adverseconditionals.com

http://wiki.nginx.org/NginxHttpImageFilterModule

I've been impressed with Dragonfly, "a Rack-based ruby gem for [image] processing/encoding on the fly"

  http://blog.new-bamboo.co.uk/2010/1/2/dragonfly

I've thought the same thing. Seems like something that needs to be done over and over. It seems like a good potential business idea as long as it's cheap enough.

I think urlimg might be what you are looking for... http://urlimg.com/

Thanks, will take a closer look, but pricing seems off (1 cent/mb/month over 50mb)

I'd be happy to build you such a service. Would be quite simple. email me- theIntuitionist@idont.no

Off topic, but why do you have all of your files browsable at http://idont.no ?

You should set up a landing page at least, so visitors don't just see /www directory.

you may want to try this: http://gaia-git.sourceforge.net/ it targets mobile devices, so could be what you are looking for.

try http://cdn-cloud.appspot.com/ despite the name "cdn", it provides functions for scaling

Thanks, looks useful, but didnt find any Terms of service or pricing info..

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