imageio: lower default jpeg quality to 95 and minimum to 5

Quality 95 offers a better default quality to size ratio.

Also, defaulting to 97, makes the slider behave slightly oddly
with a step size of 5, since it will "snap" to 92,88,... instead of
95,90,85,...

Alternatively a minimum of 1 causes the slider to snap to 1,6,11,...
instead of 5,10,15...
(cherry picked from commit 7c520cb3dcaba2be619e393c73c22f30f819c90e)
imageio: lower default j2k/jpeg2000 quality to 95 and minimum to 5

Quality 95 offers a better default quality to size ratio.

Also, defaulting to 97, makes the slider behave slightly oddly
with a step size of 5, since it will "snap" to 92,88,... instead of
95,90,85,...

Alternatively a minimum of 1 causes the slider to snap to 1,6,11,...
instead of 5,10,15...
(cherry picked from commit 0432e454e61f154dead150f69e04a666174ae143)
imageio: lower default WebP quality to 95 and minimum to 5

Also, defaulting to 97, makes the slider behave slightly oddly
with a step size of 5, since it will "snap" to 92,88,... instead of
95,90,85,...

Alternatively a minimum of 1 causes the slider to snap to 1,6,11,...
instead of 5,10,15...
(cherry picked from commit e79890e57823487a8c94a886d868b7bbc01eb6a2)