12 replies to this topic

[Phyrex]

*If you post a lot of pictures you might want to read this to optimise/lower your pictures' sizes*

A lot of pictures are being posted with insane sizes. I'm not talking about the dimensions of a picture, only the size in Kilobyte (kb).

The bigger a file, the longer it takes to download which is especially annoying for modem users.
A lot of server hosts also have a maximum of bandwidth you can use per day. So an unnecessary huge file will eat away your resources in no time leaving others with a 'no-image' pizza box.

Therefore images on the web need to be optimised.
Examples:

A typical 640x480 resolution picture is about 280 kb in size at max quality. When you lower this quality a small bit, the size will first drastically decrease (100 kb less right of the bat) while there isn't even a difference noticeable with the human eye! The more you decrease quality the less the size differences will be and at some point there's a trade-off with good quality and a small file size.
In the 640x480 resolution picture this is around 50 kb. (560% smaller and same quality!   )

You will need a program to edit pictures.
Every windows has Paint. (Start -> Execute -> type "mspaint" and press OK. Or go to C:WINDOWSsystem32mspaint.exe )
However Paint is extremely limited so if you have Adobe Photoshop for example use that.

First how to do it with Photoshop:

Open the image in Photoshop, first edit/resize it the way you want. When you're done go to:
File -> "Save for Web"
On this page there are settings, choose: JPEG High. You can use the slider on the right to increase % for better quality but the High setting/60% is optimal.

( You could also just use "Save as" under File. Select JPEG and a quality number of 5-7. Above or below this isn't recommended. )

Secondly; Paint.

Start the program, first you need to make sure the canvas isn't larger than the picture otherwise you'll get a useless white section added to your picture... In order to do so:
Go to the bottom right corner and hover your mouse over a blue dot. Your mouse will change in an arrow. Click & hold, and drag the canvas size small. When you open your picture in Paint it will automatically increase the canvas to fit the picture. (While it doesn’t decrease for some reason...)

Now that's done; Open your picture/photo in Paint. Go to: File -> Save as.
Type the name of your picture and SELECT:   "JPEG (*.jpg;*.jpeg;*.jpe;*.jfif)"
You can not choose your quality setting here but it will be about the equivalent of the Adobe Photoshop settings discussed (a bit smaller even).


Press "Save" and that's it. Your pictures are now a lot of % smaller while the quality loss (if any) is minimum and well worth the trade-off.

Notes:
Always use JPEG for photo's. All other formats are either too big or don't use a good compression for photo's.
I use XP Pro so some things might be different. If it is ask here for further help.

Happy posting.   8)

[bwdoz]

If I could add a few of my own garbled thoughts to Phyrex' post...

JPEG compression is remarkable, but it is a 'lossy' compression format and *can* degrade image quality. This isn't enormously apparent, particularly on-screen but it's there - especially if you use a lot of compression (medium or particularly low quality or equivalent). It can show up more when the image is printed. However as Phyrex says, it's a trade-off but well worthwhile for web use.

Every time you re-save an image using JPEG compression you lose a little more quality. Bear in mind that most digital cameras will have already applied JPEG compression to the image before storing it in memory. It doesn't take too many 'workings' to render a beautiful picture fairly nasty!

My point here is make sure you use a copy of your image, not the original - especially if you want to get prints from it at any time.

Bruce

[Phyrex]

That's right Bwdos, it's indeed better to edit the original versions of pictures.
Although the difference won't be huge after one re-save it can be quite significant after many...
I might also add that raising the quality setting of a low quality picture to high isn't going to make it look better (of course), since that data has been lost with the previous downgrade.


Thanks for the sticky by the way.

[Dunc]

For an example of 'over-kill' on jpeg compression see my low res ibecella photos in http://www.cpukforum...opic.php?t=5816  

I'm a PaintShop Pro fan (used it since the early shareware versions!!) and there I can 'dial-in' the compression level when saving.  jpegs are good, but not that good if you use off-line.  You can however do a bit of basic manipulation 'loss-less' if need be - maintains what your camera throws out.  A minefield of an area  :?

8)

[Pizzicara]

and if you dont have 600 dollars for photoshop, you can use http://www.ifranview.com to re-size pictures, plus a host of other features :)

[Phyrex]

Spectabilis73 said:

and if you dont have 600 dollars for photoshop, you can use http://www.ifranview.com to re-size pictures, plus a host of other features :)

I think efikim already mentioned that Spectabilis. :-)
Your link is also misspelled and not working by the way.  

Haven't used Irfan myself but the program looks pretty good on the site.
Photoshop CS (/8 ) is better of course but you only need like 0.01% of the available features for a simple optimisation so it’s a bit overkill indeed.

Edit: I misspelled "mispelled" Oh the irony...  

[fischermans]

Hello
You can use "Resize Pictures".Its a small free programm from Microsoft which get implemented in Windows XP.So when you klick with the right mouse button on a picture you can use Resize Pictures.For me the best and comfortablest programm.Here you can get it:
http://www.microsoft...ppowertoys.mspx
Regards Alexander

[Fernando Rivadavia]

Hi guys,

I often edit digital pictures with Microsoft Photo editor. I notice that the jpeg files always decrease drastically in size, no matter what sort of editing I'm doing (sharpening an image, cropping, rotating, resizing, or messing with the image balance. Does anyone know how to avoid this?

Best Wishes, Fernando

[Pizzicara]

hmm.. anyone know of a way to batch resize photos?

Yeah if you do that too much aidan, you end up getting artifacts.. which is why I prefer to shoot in raw (which actually takes up less space than tiff)

[Gawd_oOo]

photoshop does batch processes, as does photoimpact (ulead), I think fireworks does aswell.

Rather then resizing pictures, thumbnails that link to the original are alot nicer imho. load time is quick, but you can still get as much detail as possible.

Many of the free hosts give you the coding to post thumbnails right when you upload the pictures.

Here is an example: (btw I know my camera blows, getting a new one in 25 days    Pretty sure most phones have higher quality pics then my current camera)

The group shot.


Pinguicula ehlersiae X oblongiloba


Pinguicula 'Aphrodite'


Utricularia livida


Drosera capensis 'Albino'

[Andy Collins]

A web site that will resize your images and it's free. Works very well too.

http://www.picresize.com/