Re: jpeg resize - file size increases

From: Lloyd (lloydkl.tech_at_[hidden])
Date: 2020-07-24 06:28:21

On Fri, Jul 24, 2020 at 4:51 AM Gavin Lambert via Boost-users <
boost-users_at_[hidden]> wrote:

> On 23/07/2020 23:42, Lloyd wrote:
> >
> > Thanks a lot for your help.
> >
> >     Probably the important part is what your T() is.
> >
> > T is the format of the source file. In the case of jpeg, it is
> gil::jpeg_tag
>
> That means you're using 100% quality by default.  To reduce the file
> size you'd have to change this, as I said.
>
> >     When calling write_view, you can specify a JPEG quality explicitly
> via
> >     something like image_write_info<jpeg_tag>(95) -- use a lower number
> for
> >     a smaller file size but more artifacting.
> >
> >     If you don't specify it, GIL uses 100 by default (which might be
> >     excessive).  Other editors probably use different values by default,
> >     which might be causing the file size increase you're seeing.
> >
> >
> > May i know what do you mean by "Other editors" ?
>
> Whatever image editor that originally created or last edited the file.
>

Thank you very much