* gnus-picon.el: New implementation.

* gnus-picon.el: New implementation.

* mm-decode.el (mm-create-image-xemacs): Separated out into
function.
(mm-get-image): Use it.

* gnus-art.el (gnus-treat-display-picons): Simplify.
(gnus-treat-from-picon): Renamed.

* gnus-ems.el (gnus-create-image): New function.
(gnus-put-image): New function.

* gnus-art.el (gnus-article-treat-unfold-headers): Doc fix.
(gnus-with-article-headers): New macro.
(gnus-article-goto-header): New function.

* gnus-xmas.el (gnus-image-type-available-p): New function.

* gnus-ems.el (gnus-image-type-available-p): New function.