>>1561080
.cbz and .cbr are just zip and rar files.
Rename your file extension to zip/rar extract the images and use something like ffmpeg to batch lower the resolution or image quality. Zip/rar them back up and rename the .cbz/.cbr

>>1561081
Well, that still leaves me with a .cbz. I need them to be a .pdf.

>>1561085
Use Calibre to convert.

>>1561085
Extract your batch of images. Install FastStone Image Viewer:
https://www.faststone.org/download.htm
Launch FastStone, click Create>Multi-page File Builder
Play with the options, it has drag and drop if you wanna change page orders or whatever

>>1561080
GIMP?

>>1561080
Use imagemagick, the CLI tool.
magick * output.pdf
You might need to use the word 'convert' instead of the word 'magick' depending on how you install it.

You can combine it with 7-zip to make a script that will automatically pdf all of your .cbz files:
ls *.cbz | ForEach-Object {
$folder = "$_" + "_folder"
$outputpdf = $_.BaseName + ".pdf"
mkdir "output"
7z x $_ -o"$folder"
#rm "$folder/*.txt"
magick "$folder/*" output/$outputpdf
echo "$($_.Name) has been converted into $outputpdf"
}
This will make an output/ folder and stick the pdfs inside it. It doesn't do the ffmpeg compression, though it seems you've already done that. The commented rm command is for if the .cbz contains pesky .txt files.
The magick command here relies on the filename ordering to get the pages in the right order.

>>1561080
Select images
Right click
Print
Choose printer: Microsoft Print to PDF

>>1561080
Download CDisplayX
Open the CBZ file with it
Right click > File > Print...
select Printer name: Microsoft Print to PDF
print range All
Hit OK, name your PDF, done!

>>1561212
>>1561216
>Microsoft Print to PDF
While by far the most convenient option, it's also the worst. It's only to be used if you don't give a single fuck about anything on the pdf

>>1561221
If OP is reading it on a handheld device, I doubt he'll be able to tell the difference.