Re: how to detect if a jpeg file is progressive or not

[Olafur Jens Sigurdsson <ojs@klaki.net>]

Þann 2006-05-31, 17:12:36 (-0400) skrifaði H.S.:
> 
> Hello,
> 
> I have searched google but haven't found an answer I was looking for. I
> want to upload some family pics to share among relatives. Some have
> dialup connections. To facilitate image downloads in their browsers, I
> want to upload progressive jpegs. How do I find out if the jpegs I
> already have are progressive or not? If they are not, how do I convert
> them to progressive jpegs?
> 
> I have:
> ii imagemagick   6.2.4.5-0.8

Imagemagick does the trick for you.

To see if your files are interlaced or not you can use identify
-verbose filename.jpg and search for the Interlace line and if it says
None then it isnt a progressive jpeg and if it says Plane it is.

To convert from basic to progressive use convert infile.jpg -interlace
Plane outfile.jpg

HTH

Oli