New control "picture"
I offer to enter new control
If user press it, then browser show local file system.
User can choose only one file in it, and only graphic file.
After user has chosen such file
(for example, containing photography of tiger),
picture from this file will be shown instead of initial gray rectangle,
but picture will be shown also without four corners
(to distinguish control from
which is displayed as gray rectangle with cut corners
at once after loading of document.
If user press on this picture once more, then explorer will appear once again,
and user can change graphic file.
This file will be
in the following way
<a b=animal c=uniqueId />
<?file attr=c value=uniqueId xml:size="31">Y29udGVudHMgb2YgZmlsZTEudHh0</file>