If you want to apply your logo or watermark to many photos, you might consider creating a Photoshop brush of it for easier application. It only take a few minutes.
(Note: the downside to using a brush to apply your logo is that it’s monochromatic. Because my logo is multiple colors and I like it to display that way, I don’t use a brush to apply it.)
To create a brush, start a new document in Photoshop and set the Background Contents to Transparent.
Draw/type/create your logo.
When you’re done, use the rectangular marquee tool to draw a box around everything you want included in the brush.
From the menus, select Edit > Define Brush Preset.
You’ll now see your new brush in the brushes palette.
If you’d like the logo to blend a little better with your photo, try reducing the opacity some. You can also use the size slider to adjust the size of the brush – or (TIP!) you can use the left and right brackets [ ] to decrease or increase the size of the brush.
Apply to your photo and you’re done!