Legacy ImageMagick Discussions Archive

Hi

Sorry for this (perhaps stupid) question, but I haven't found the answer anywhere on the internet.

Does a change in /deletion of the metadata (e.g. convert +profile 8BIM -profile 8BIMTEXT:iptcData.iptc imageA.jpg imageB.jpg) affect the image quality?

Or does such a change only affect the header of the image file where the metadata is stored and leave the image itself intact?
If it does change the image quality, how is then the best way to change the metadata? (Xnview?)

Or perhaps a more generalized question: Which commands of IM do have an influence on the image quality and which do not?

Thanks

Loll

This will read in and write out the image DATA as such it will suffer JPEG data loss.

other JPEg specific format handlers may be able to do it without loss. Though changing a color profiles will still need actual image data changes.

So there is no way with IM to change the header of an image (where the metadata are stored) without changing the image itself?

It is very specific to the JPEG file format. ImageMagick is a General Raster Image processor, and as such always reads in the image to process it. It does not handle direct changes to a specific image file format, unless such a function has been declared as a special "External Delegate Program".

Have a look a JHead or other JPEG specific programs.