If you want to resize individual images and you have the full package, it will probably be easier to resize them with Corel Photopaint.
Image : Resample will give you the main options. You probably want about 96 dpi. Set that first and then choose your desired display size in either pixels or a measurement.
Bear in mind that the file size shown on that screen is an uncompressed file size. The size of the compressed file will be a lot smaller, but you don't see that until you save the file.
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You can also do it in CorelDraw, but you can't open a JPG file directly in CorelDraw. You will have to use an empty page, import the jpg (only one at a time) and export them again (making sure to select JPG as export type).
In this case, you can select the image and use Bitmap : Resample to choose your resolution. However, you'll find when you go to File : Export you'll again be asked to set a resolution. So in fact you can skip the Bitmap Resample step and just go straight to the export.