There are two variables that affect the size of the image and its file size.
The first is the dimensions of the picture. Most people reading this have their screen resolutions set at 800x600 or 1024x768 (or something in that range). Therefore, since their screen is at most 1024 pixels wide, putting up an image that is 1600 x 1200 or larger simply means they won't be able to see it all at once.
Try to resize your images in your photo/image editing software so that they are approximately 800 pixels wide or less (maintaining the original ratio of width to height of course).
Just for reference, this pic of the little pygmy rattlesnake is 533 x 432 pixels and has a saved file size of 35KB. Big enough to share, yet small enough to be able to store a lot of pics within KS.com's 1 mb limit.
The other thing that affects file size is the amount of jpg compression. With most images, you can actually set a fairly high amount of compression without an extraordinary amount of physical difference. For online posting, I usually use a setting of about 70% compression (setting 3 in photoshop). Different programs label this in different ways. You will have to learn how your program does it to figure it out for yourself.
Many times there will be a slider that shows the tradeoff between quality and file size. So one end of the slider will say high quality and the other will say high compression or small file size. Choose closer to the small file size end of the continuum. The loss in quality is usually negligible and the file size benefit is large.
One other tip. While you are experimenting with compression, start with your original image each time and try different levels of compression. Then save the compressed image as a new file. Don't keep reopening and resaving compressed images as this will quickly degrade quality.

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Chris Harrison