For images you want to put into your website (excluding the photo gallery, which automatically resizes the images for you) you will need to make sure they are at least under 500x500. This means 500 pixels wide by 500 pixels in height. Once you have the image under those sizes, you will not have any problems uploading it. Plus, once the image is under 500x500, you CAN resize it further without loss of quality within the wysiwyg editor. Below are instructions to get your image to below this 500x500 mark. (That limit is set in the first place for your protection so that the images you put on the site will not stretch out the width of your site and thus ruin the page layout).
You can use this great new website called Quick Thumbnail OR you can follow the intructions below using a program on your computer.
Download this great program called irfanview. EVERYONE should have this program on their computer. The link to the site is here at http://www.irfanview.com/ . Download the program to your computer and install it. It will ask during the install process if you want to associate any file types with this program. Select 'image files only.' Finish installation.
Now that the program is installed, you simply find the image on your harddrive that you want to resize and double click on it. It SHOULD now open in this program irfanview if you associated images files with this program.
With the image open in irfanview, either go to image>resize/resample... or click ctrl+r on your keyboard. This will bring up the resize image dialog box.
Under set new size , change both numbers and make sure they are both under 500.
Click File>Save as to save the file and give the file a name in the file name field. ALSO, there will be a JPG/GIF save options dialog box that opens up on the top right of the screen. MAKE SURE ITS SET AT 95 or ABOVE.
Now click the save button. Your new resized image is now ready to upload.