When I run
convert *.jpg output.pdf
the output looks like this:
Why is the first page bigger then the others in the PDF? The original JPEGs were all the same size!
I had the same problem. The main issue of this is different resolution of your images you want to convert to pdf file.
Use below command (like cjm mentions) to check the resolution of your photos.
All images you want to convert to pdf file should be in the same resolution like ex: 72x72. This give you more less equal size each one of your pdf pages.
I had the same problem and cjm's comment pointed me in the right direction, but didn't give me a solution. I found the solution was to specify the DPI manually with the -density option:
A JPEG image can store a resolution (i.e. pixels per inch) in addition to its geometry (actual number of pixels).