On Fri, Jul 24, 2020 at 4:51 AM Gavin Lambert via Boost-users < boost-users@lists.boost.org> 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
(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