Here is the article I pulled these gems from:
Construct complex layer names
You can specify multiple asset names with parameters while naming a layer for asset generation. For example:
120% Delicious.jpg, 42% Delicious.png24, 100×100 Delicious_2.jpg90%, 250% Delicious.gif
Photoshop generates the following assets from this layer:
- Delicious.jpg (an 8-quality JPG image scaled 120%)
- Delicious.png (a 24-bit PNG image scaled 42%)
- Delicious_2.jpg (a 90%-quality JPG image that has an absolute size of 100×100 px)
- Delicious.gif (a GIF image scaled 250%)
Do I need to specify unique asset names?
Asset names must be unique at a document level.
What is the default quality level at which image assets are generated?
JPG assets are generated at 90% quality by default. PNG assets are generated as 32-bit images by default. GIF assets are generated with basic alpha transparency.
Does Photoshop generate image assets from layers with transparency and other effects?
Yes. Transparency and other effects applied to a layer are reflected in the assets generated from that layer. However, such effects may be flattened in the generated assets.
How are image assets generated from layers that bleed off the canvas?
Assets are clipped to the document boundaries. If an image does not fall within the document boundaries, Generator does not create the associated image assets.
Is the comma the only permitted separator between image asset names?
In addition to the comma (,), you can use the plus (+) symbol as a separator between image asset names. For example:
42% Rounded_rectangle_1.png24 + 100×100 Rounded_rectangle_1.jpg90%
is the same as:
42% Rounded_rectangle_1.png24, 100×100 Rounded_rectangle_1.jpg90%