# How can I shrink image from 1.75 Mb to 200Kb without changing the dimensions?



## cvandy (Feb 7, 2008)

HI,

I am trying to change lower the file size of an image so that I can upload it into our crm software for a mass email. The file size is 1.75Mb. The crm software will not let you upload anything above 200Kb. If I change the dimensions of the image it will be unreadable so this is not an option. So the dimensions need to stay the same but the actual file size needs to shrink to 200Kb. Thanks ahead of time for your help


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## Armiris (Sep 6, 2007)

Compress it into a zip archive, a rar archive, or another compression format.


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## cwwozniak (Nov 29, 2005)

What is the current file format (JPG, GIF, PNG, TIF, etc.)?

What kind of image is it (photograph, line drawing, cartoon)?


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## cvandy (Feb 7, 2008)

It is a jpg and it is an advertisement like you see in a newspaper. It has to stay jpg as well and zipping it will not work


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## caraewilton (Nov 7, 2007)

I have a suggestion, could you not use irfanview to change the dpi. Maybe 96 dpi.
This should make a difference and there is a setting which allows you to keep the orginal size. I have just experimented. Reduced a 9mb file down to 2mb.

As an aside, my understanding is that jpg are compressed thus zipping them will not change the size. Is this correct?


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## fairnooks (Oct 1, 2007)

You'll do well using Fast Stone Image viewer. You open up the image and then save as..., click on advanced and set the compression slider to more compression and then click on update preview and note what the new filesize will be. Keep adjusting the compression and updating the preview until you have the new image size where you need it to be.


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## cwwozniak (Nov 29, 2005)

caraewilton said:


> I have a suggestion, could you not use irfanview to change the dpi. Maybe 96 dpi.
> This should make a difference and there is a setting which allows you to keep the orginal size. I have just experimented. Reduced a 9mb file down to 2mb.
> 
> As an aside, my understanding is that jpg are compressed thus zipping them will not change the size. Is this correct?


I am not familiar with irfanview but it sounds like it is reducing the number of pixels in the picture to make the file smaller. To do that it is combining multiple pixels into one. That is also a one way path. There is no way to accurately expand a single pixel into multiple pixels with their original colors. If you tried printing the reduced sized file at the same physical size as the original, the result would appear a lot more blurred and pixelated.

You are correct that a jpeg file is fairly well compressed to begin with. Zipping it may reduce the file size by a fraction of a percent.


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## caraewilton (Nov 7, 2007)

Hi Fairnooks. DPI refers to how many dots are used to make the picture in a square inch measurement. Compression in terms of jpg means the amount of dots removed and then algorithms used to replace the missing info. Is this correct? What is better, lower dpi or higher compression? Which gives you the best image at the end of the day? I mean you can reduce dpi until you have the desired file size, alternatively you can increase compression until you have the required file size. So which method would leave you with the best looking picture?

Sorry I think I am asking lots of technical type questions? Just was wondering?


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## caraewilton (Nov 7, 2007)

cwwozniak said:


> I am not familiar with irfanview but it sounds like it is reducing the number of pixels in the picture to make the file smaller. To do that it is combining multiple pixels into one. That is also a one way path. There is no way to accurately expand a single pixel into multiple pixels with their original colors. If you tried printing the reduced sized file at the same physical size as the original, the result would appear a lot more blurred and pixelated.


I have found that 96dpi still looks fine on screen but when you print it, it looks blurred. My understanding is, this occurs because you are using bigger dots (pixels) to fill the same amount of space.
Most printers print at 300dpi which is why if you want to print something, it should not be reduced more than 300dpi.
I guess screens use fewer dpi to full the screen thus 96 is still okay.

I am not sure if all this is correct, maybe chuck or fairnooks can comment.


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## fairnooks (Oct 1, 2007)

I wouldn't mess around with the dpi settings in this instance. I believe it was for a mass email, not printing, and not all programs have the option to lock print dimensions when resizing (changing dpi), and if they do the image still has to be rendered just like it has to be for straight compression in order to hold the dimension the same (normal dpi change always changes dimensions relative to viewing or printing).


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## PopPicker (Sep 21, 2004)

A 1.75 mb jpg is an awfully large file when opened at 72 dpi. I'm sure reducing the pixel size will not compromise quality.

Perhaps more info on the actual size (pixels not kb) required would help. For email advertising an image size of 600x800 is AMPLE if not too big!

PP


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## cvandy (Feb 7, 2008)

Thanks for all of the responses. I plan to try both changing the dpi and the compression. I cannot get to the websites to download the software right now because our network is blocking them. I will have to download the irfan view and fast stone when I get home.


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## cvandy (Feb 7, 2008)

also the picture is 792x756


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## fairnooks (Oct 1, 2007)

I was about to say you guys were probably right unless it was a long ad image superimposed or integrated with a tall building or something of the kind. Cvandy never mentioned having to scroll the image though and if the text (or whatever it is that needs to be readable) couldn't be any smaller, and assuming 100% viewing size, I had the wild thought that the filesize reported may be that of the bitmap image in memory and not the actual .jpg filesize.

So almost certainly you are closer to the 200 Kb filesize than you think cvandy. You should still get a very reasonably good quality image with compression if its a high qualtiy .jpg to begin with. Good luck.


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## lister (Aug 10, 2004)

DPI is metadata in the image that tells the printer how many pixels to print in an inch, adjusting it will not alter the image at all, neither will it make the file size smaller.

To keep the pixel dimensions the same and make the file size smaller you will have to increase the amount of compression in the jpeg save dialogue.


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## PopPicker (Sep 21, 2004)

An image the size you say with a DPI of 72 creates a jpg file size of around 400kb which is 1.7mb when open. Saving it at a slightly... VERY slightly... higher compression reduces it to a little over 100kb. With no noticable loss of quality when viewed at 100%

PP


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