Upscaling photos (JPG) and maintaining quality!

[NicolasRobidoux]

@theonlysandman: Turn off chroma subsampling, and up the JPEG quality: http://www.imagemagick.org/Usage/formats/#jpg_write

[Bonzo]

@Bonzo: Most people will find the results of stair interpolation disappointing compared to the best ImageMagick methods.
Stair interpolation is basically a way of mitigating the shortcomings of "primitive" upsampling methods.

Thanks for the update NicolasRobidoux I did not know of the method and thought it could be an option.

[NicolasRobidoux]

http://jeanbruenn.info/2011/10/30/upsca ... -resizers/
http://www.avsforum.com/t/1477339/so-yo ... t_23430408

[NicolasRobidoux]

@theonlysandman: identify -verbose shows that both the "before" and the "after" images (which I believe are misleadingly labeled) are chroma-subsampled. This is probably why the red door is a problem.

[theonlysandman]

Thanks again for all the discussion, especially about the what came first the chicken-before or the chicken-after.

Basically, I have been 'guaranteed' the before (320x240) is the real before and the after (640x480) is really the after.
The reason, the real estate board only sends out the 320x240 photos; their technology made the guarantee...and they would be in huge trouble if they sent bigger files to one company and not the next....

ImageMagick community! You rock...I found the solution...as I was typing the above... I realized you guys are experts and if you say the after was the before... then well it must be! So, I check the technology providers website...to check a listing...

So I went here:
http://www.homesacrosscanada.com/listin ... na-street/

then look at their photos:
http://photosrv.filogixdms.com/photosrv ... 72020b.jpg

Noticed the 'b'...and tried
http://photosrv.filogixdms.com/photosrv ... 72020a.jpg

It works! There is the 640x480 pic...already to be scraped and used!

Without all your discussion and comments I would never have found this! Thank you so much for your help.

If anyone is ever in Toronto...drop me a line...beer or wine or food is on me!

Thanks again!

[Bonzo]

Going off topic but it is not very professional to take a photo from a car showing part of the door and wing mirror when trying to sell a house!

[NicolasRobidoux]

@theonlysandman: Better than wine and dine: Get yourself a Flattr account and thank Cristy, the tireless main developer of ImageMagick, by clicking on the little green button at the top right of this window. We all owe Cristy big time.

[NicolasRobidoux]

The foremost thing you should consider when specifying a image to resize is...
Do you really want to modify the image?

(Anthony Thyssen http://www.imagemagick.org/Usage/resize/#resize)

[theonlysandman]

@NicolasRobidoux Thanks for the heads up about Flattr...Cristy has been flattred!

Defiantly better then beer since in 20+ years of using forms only one person has ever taken me up on it!

Merry Christmas everyone!