https://imagemagick.org/script/command-line-tools.php
https://tecadmin.net/install-imagemagick-on-linux/
Step 2 – Install ImageMagick
After installing required packages, let’s install ImageMagick using the following command. ImageMagick package is available under default apt repositories.
sudo apt install imagemagick
https://superuser.com/questions/1255867/how-to-convert-png-to-pdf
You are almost certainly seeing references to ImageMagick, which has a "convert" utility that potentially allows .png to .pdf conversion e.g.
convert image1.png image2.png image3.png output.pdf
First convert the image to PDF
convert image.png image.pdf
Then scale up and offset the image using pdfjam (another free tool)
pdfjam --paper 'a4paper' --scale 0.3 --offset '7cm -12cm' image.pdf
Then combine both PDFs using pdftk
pdftk text.pdf stamp image.pdf output combined.pdf
You may need to download STAMPtk if you need to position the image and add it to only one page in the general PDF, but this one you have to pay for it.
You can download STAMPtk from here http://www.pdflabs.com/tools/stamptk-the-pdf-stamp-maker/
http://www.imagemagick.org/discourse-server/viewtopic.php?t=32470
You need an output image and an input image and the extra page image. So if you have 1.pdf and want to add 1.jpg, you would do
CODE: SELECT ALL
convert 1.pdf 1.jpg 1.pdf
But Imagemagick will rasterize your pdf. So any vector data will not be preserved. Also you may need to specify the density for decoding your input pdf.
CODE: SELECT ALL
convert -density XXX 1.pdf 1.jpg 1.pdf
http://www.imagemagick.org/discourse-server/viewtopic.php?t=31615
A PDF with a single page, with a single image that is a combination of all the input images? Then:
CODE: SELECT ALL
magick montage *mhk* -mode concatenate -tile 1x out.pdf
CODE: SELECT ALL
magick *mhk* out.pdf
magick convert rose.jpg rose.png
Next, we reduce the image size before it is written to the PNG format:
magick convert rose.jpg -resize 50% rose.png