This solution is for people with Windows computers. Not overly technical, but it worked for me. You will need Windows Live Photo Gallery (comes with most modern computers or download it, and download Picasa (Google it)
Another way:
Download Irfanview. It will do the job.
Resizing the picture in Irfanview ,
Click the file tab,
click open to import the image,
click image tab,
click Resize/Resample,
select new size as 600x600,
Disable aspect ratio,
Press ok.
click on File,
click save as, to save the image/picture.
Use a photo editing program. Commercial ones like Photoshop Elements, Corel PhotoPaint can do this, as well as open source programs like Paint.net
That means the picture your taking will have 600x600 pixels.
Pixels are a measurement of the resolution of an image. For example, old laser printers used to print in 300x300 pixels per inch, then came 600x600 prints. I'm sure you're asking "Why are you talking about laser printers when I asked about pictures?" Because the premise is the same. An image that is 1 inch by 1 inch that use the 600x600 resolution would have a file size roughly twice that of a 300x300 resolution. All of that to tell you that no one can really tell you, you will have to find the resolution of the image, find out how many pixels are in a square inch of that resolution, then multiple it by the size image you have.
Normally you need printed passport photos and hence no need to worry about pixels. However if you applying for certain types of non-immigrant visas or for lottery visa for USA, here are the dimensions in pixels.Minimum acceptable dimensions are 600 pixels (width) - 600 pixels (height). Maximum acceptable dimensions are 1200 pixels (width) - 1200 pixels (height).For full details about 2x2 digital image for DS 160 or DV visa, check the related link.
If you are in India, the passport photo size is 35x35mm. However if you are in the USA and are renewing or applying for Indian passport with any of the Indian consultes, they will take 2x2 inch or 51mmx51mm sized photos.
64 pixels.64 pixels.64 pixels.64 pixels.64 pixels.64 pixels.64 pixels.64 pixels.64 pixels.64 pixels.64 pixels.
small pixels
one megapixel is a million pixels, so 9.2 mega pixels would be 9.2 million pixels, or 9,200,000 pixels.
The Indian passport regulatory document states the size to be 3.5cm X 3.5cm but this would create a square shaped photo and in India, most of the passport size photos are in a rectangular shape so set it to 3.5cm X 4.5cm.
123,200 pixels = 0.1232 megapixels.
Pixels
12 pixels tall 12 pixels wide.
it is 150xa50 pixels.