ImageMagick: batch resize and DPI change

mogrify -resize 59.06% -density 150x150 *.tif
mogrify -resize 1024x1234 -density 150x150 *.tif
If the images are in grayscale than the above will convert them to RGB. Thus one can use the following: mogrify -resize 59.06% -density 150x150 -colorspace gray -layers flatten *.tif
mogrify -resize 1024x1234 -density 150x150 -colorspace gray -layers flatten *.tif