Open an image (or shoot one within Snapseed). Tap the plus sign on the lower right of the screen to open the menu of tools and filters (inset at right). To straighten the image, tap Transform. Swipe down on the screen to choose Rotation. Place a finger (or stylus) in one corner of the image to rotate, and use the guidelines to achieve a straight horizon. Tap the icon in the upper right to see before/after views. Tap the check mark to apply or the X to cancel.
Use Control Points for Selective Adjustments
Tap the plus sign to open the menu of tools and filters. Choose Selective. Make sure the word “Add” (or the plus sign on a smartphone) is blue (active) on the first screen. Tap the area of the image to be adjusted. The default setting is Brightness. Swipe down to choose Contrast or Saturation. Move the Control Point or pinch/zoom to see and adjust the mask as needed. Swipe left/right to modify intensity. Tap to add additional points if/when necessary. For this image, I placed four points: one point (B) with broad coverage to darken the sky and its reflection and three points (not shown) to add saturation to the light colored grasses in the lower right.
Paint on your changes
Click the plus sign to open the Tools and Filters menu again, but choose Brush this time. Tap Effect to select the type of adjustment you want to make (I chose Exposure to lighten the shadows in some of the trees). To see the mask as you work, tap the eye icon. Tap Decrease or Increase to select intensity. Pinch to zoom in; use the navigator box to select the area you want to work on, then paint in the adjustment. To erase what you’ve done, set the effect’s exposure to zero then paint it out.
Apply some tonal contrast
To add more punch to the image, head back to the menu and use one of the new filters to add specialized contrast. Click on the plus sign to open the menu, choose Tonal Contrast from the Filters menu. Swipe up/down on the image to select a contrast option. I chose Midtones to bring out overall contrast and enhance details. Swipe to the right to add contrast (I adjusted this to 51; there is no option below zero).
Use Stacks to apply or adjust your final tweaks.
From the main screen, tap the number next to the Save button to open Stacks. Click on a stack to see what the image looks like up to that point. Tap the left arrow to open the flyout for each tool or filter if you want to readjust, mask out a portion, or delete. I decided I didn’t like the exposure adjustment I brushed on in Step 3 and clicked the Trash icon to delete it. Alternatively, I could have selected the slider icon, which would take me back into the brush adjustment step for additional tweaking. Some adjustments offer a third choice to apply/erase the effect with a mask. Tap Close when you’re done.
Save and share your work
Tap Save to save the image as either an original or a copy (I prefer the latter). To share, print, or perform other actions, tap on the three dots in the upper right. Choose Share to share the image via email, Message, iCloud, Google+, for example. Or, if you want to work on the image in another app, tap Open In to see a list of options, such as Instagram, among the apps you have installed.