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climb4free
Aug 4, 2009, 4:33 PM
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I see all kinds of photos posted in forums, the quality looks decent. When I try to shrink down photos to 150 KB or smaller (to be allowed to attach them) they look all distorted and pixelated. Any pointers on how to get them to look decent and still fit the file size requirements.
Thanks for the help.
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blueshrimp
Aug 4, 2009, 4:38 PM
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Use a higher resolution camera.
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climb4free
Aug 4, 2009, 4:45 PM
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That's not my question. I have a high resolution camera. 5.1 MPix. This site only allows 150 KB file size. That is tiny... how do I shrink the file size without killing the photo?
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shrug7
Aug 4, 2009, 4:49 PM
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Registered: Oct 18, 2006
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Photoshop
The GIMP
iPhoto
etc...
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blueshrimp
Aug 4, 2009, 4:52 PM
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I use GIMP. Just go to Image->Scale, and give it the max pix width you want (A 500 by 500 pixel is about 100kB). Works for me.
For the photos I've posted here I've done some cropping too (i.e. crop before scale, or just crop to proper size without scaling at all, if you can manage that without cropping the subject out of the picture altogether). That might give you a few extra pixels so that it doesn't look so pixelated.
Also, the pixelation may come when the website scales your picture to display it bigger than the small size you uploaded. Maybe one of the website people here can comment on this one and if true, maybe it is time to start accepting bigger pictures so that they don't have to be scaled to bigger?
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climb4free
Aug 4, 2009, 4:54 PM
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blueshrimp wrote: ..., maybe it is time to start accepting bigger pictures so that they don't have to be scaled to bigger?
I agree.
Thanks for the input
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bennydh
Aug 4, 2009, 5:09 PM
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In photoshop, you can save the quality of photos at different levels. There is also the file size of the photo for each setting. Additionally, there is the option of saving as a gif and dithering, and png formats.
The image or canvas size doesn't necessarily decrease as a function of file size, and image quality.
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Hennessey
Aug 4, 2009, 7:29 PM
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blueshrimp wrote: maybe it is time to start accepting bigger pictures so that they don't have to be scaled to bigger?
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qwert
Aug 5, 2009, 8:12 AM
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Most has been already mentioned, but here are some additional points:
File size is not directly a function of the image size, but at the same quality, a smaller image has a smaller file size. so i am mostly going for a width of around 1000 pixels.
More important is the image quality. One thing is the resolution. somehow i dont exactly get it how it works (should be covered by the image size, but in most programms you can change the resolution. Often it is at around 300DPI. while that makes for good looking images (depending on the subject  ) it also makes for a large file size. for uploading here something like 70DPI should be enough).
And probably the most important thing is the image quality. with most programs you have a slider for the quality (~rate of compression) when you save a .jpg. How good the results are depends on the programm you use, but generally the higher the quality, the bigger the file sizes - and the other way round. As said it depends on the programm, but values between 60 and 80 work quite good (you have to play around a bit).
Important!: before you resize a picture, and safe it in lower quality make a copy of it! some programms do that automatically, or offer non destructive editing, but if not: .jpgs dont like beeing edited. your original also will loose quality.
What programms can you use:
Photoshop. the industry benchmark, but full license is a few 100 (or 1000?) $. there are lite versions, and you probably got one with your computer. They suck, but for this they should be enough.
GIMP. Free and open source cross platform photoshop alternative. It has still some way to go before its equivalent to the full photoshop, but it beats the lite versions by lengths. also quite complicated, but as long as you just want to resize and change the quality its easy.
Preview. the standart viewer appplication on mac OSX. can also change the quality of .jpgs.
I think irfan view for windows can do so too.
And then there are all kinds of image database programms that can do this too. I havent tried it, but picasa should work, or iphoto. My favorite is digikam, howver that is a bit hard to get to run on non linux systems.
hope that helps
qwert
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Peasley1
Aug 5, 2009, 2:06 PM
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qwert wrote: More important is the image quality. One thing is the resolution. somehow i dont exactly get it how it works (should be covered by the image size, but in most programms you can change the resolution. Often it is at around 300DPI. while that makes for good looking images (depending on the subject ) it also makes for a large file size
The reason why resolution effects file size is because it changes the amount of compression, which is what the jpeg image format (and other formats) does, it compresses the image (lossy) to make the image smaller and it does this by having a "dictionary" of colors. So say you have a lot red in your image then instead of storing a 32 bit (4 byte) number (alpha, red, green, blue) it might convert all the "reds" to a single binary 1 (this is oversimplified). So instead of having 4 bytes for every red pixel you could have 1 bit for every red pixel, 1/32 the size. Obviously there many shades of red and the resolution affects what is classified as red so a low resolution will have many combinations of RGB values that is classified as red while a really high resolution might have 255, 0, 0 as it's only red. So if you have a really low resolution it will have less definitions of colors in the dictionary as oppossed to a higher resolution which effects file size.
.bmp on the other hand has no compression whatsoever it has 32 bits per pixel plus the .bmp header, so if you're looking to shrink image size without cropping or scaling .bmp is not the way to go.
Hope that explains why the resolution effects the image size.
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peanutnb85
Aug 7, 2009, 5:36 PM
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I just use Microsoft. If you have a PC go to Programs->Microsoft Office->Microsoft Office Tools-> Microsoft Office Picture Manager.
Upload your photo and then go to "edit" in the right hand toolbar.
Go to "Resize" in the right hand tool bar.
It gives you options to automatically format the pic for websites, emails, and powerpoint presentations.
Hope this helps.
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marc801
Aug 7, 2009, 5:46 PM
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peanutnb85 wrote: I just use Microsoft. If you have a PC go to Programs->Microsoft Office->Microsoft Office Tools-> Microsoft Office Picture Manager.
Other options are the free FastStone Photo Resizer:
http://www.faststone.org/FSResizerDetail.htm
Gimp: http://www.gimp.org/
And Google's Picasa can do basic resize, plus you get a web album as well with 1G of space:
http://picasa.google.com/
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