I did something likeconvert -page A4 -compress A4 *.png CH00.pdfBut the 1st page is much larger than the subsequent pages. This happens even though the image dimensions are similar. These images are scanned & cropped thus may have slight differences in dimensionsI thought -page A4 should fix the size of the pages?
convert images to pdf: How to make PDF Pages same size
pdf;conversion;imagemagick
Last time I used convert for such a task I explicitly specified the size of the destination via resizing:$ i=150; convert a.png b.png -compress jpeg -quality 70 \      -density ${i}x${i} -units PixelsPerInch \      -resize $((i*827/100))x$((i*1169/100)) \      -repage $((i*827/100))x$((i*1169/100)) multipage.pdfThe convert command doesn't always use DPI as default density/page format unit, thus we explicitly specify DPI with the -units option (otherwise you may get different results with different versions/input format combinations). The new size (specified via -resize) is the dimension of a DIN A4 page in pixels. The resize argument specifies the maximal page size. What resolution and quality to pick exactly depends on the use case - I selected 150 DPI and average quality to save some space while it doesn't look too bad when printed on paper. Note that convert by default does not change the aspect ratio with the resize operation:Resize will fit the image into the requested size.  It does NOT fill, the requested box size. (ImageMagick manual)Depending on the ImageMagick version and the involved input formats it might be ok to omit the -repage option. But sometimes it is required and without that option the PDF header might contain too small dimensions. In any case, the -repage shouldn't hurt.The computations use integer arithmetic since bash only supports that. With zsh the expressions can be simplified - i.e. replaced with $((i*8.27))x$((i*11.69)).