See http://www.imagemagick.org/script/comma ... php#resize
for relevant IM command-line convert options: resample, resize, scale, sample
all do variations of what you want with varying quality controls.
convert small.tif -density 72x72 -units PixelsPerInch -resample 300x300 -format jpg -quality 100 print.jpg
Resize a small display image to print at the same size and similar quality on a 300 dpi printer.
The quality option actually affects the lossiness of the jpeg compression algorithm in this case.
convert small.jpg -resize x700"<" bigger.jpg
Resize images smaller 700 pixels wide to that width while preserving aspect ratio.
Questions regarding crystal reports are probably better answered in their forums and knowledge bases:
http://www.businessobjects.com