How to improve image output get it with montage ImageMagick -

i joined images using montage resolution of image output less images input.

my images input have 640x480 each

but output 256x378

i searching in web , didn't find solution improve output of image quality.

the montage command i'm using

montage -tile 2x3 1.png 2.png 3.png 4.png 5.png 6.png -resize 1024x1024  montage_png.png 

anyone know how can better output resolution?

suggestion 1

try way... let montage organise images montage , pass result on convert resizing of result.

montage -tile 2x3 1.png 2.png 3.png 4.png 5.png 6.png miff:- | convert miff:- -resize 1024x1024 montage.png 

the intermediate image passed miff (magick image file format) preserves detail , metadata , quality.

suggestion 2

if 5 or 6 images , not hundreds, can in 1 go convert this. need know +append joins images in row , -append joins images in column. joining 1&2 in row, 3&4 in row, 5 & 6 in row , putting 3 rows in stack , resizing result.

convert [12].png +append \( [34].png +append \) \( [56].png +append \) -append -resize 1024x1024 result.png