• Fix the Imagick driver painting a "black box" when pasting an image with transparent areas at an alpha lower than 100; the opacity now scales the existing per-pixel alpha instead of overwriting it (#878, @nlemoine)
• Fix the Imagick driver inverting the alpha channel in effects()->negative() (an opaque image became fully transparent); it now excludes the alpha channel, matching the GD driver (#877, @nlemoine)