If you prefer to not use the Mac Photos app, or would like to store some of your photos in a different way, a viable alternative is to simply store them as files in folders. You can use subfolders, file names, comments and tags to manage and organize these pictures. You can use the four different Finder views to view the photos, and Quick Look and Preview for other views and editing. You can even use aliases to create albums.
Most people use albums to organize their photos in the Mac Photos app. However, it makes more sense to use Keywords instead of albums. You can create a Smart Album with any Keyword. But instead of Smart Albums, which can't be seen on iOS, you can simply search for a Keyword to view those photos just as if they were an album. You can also search for words in titles and descriptions, making them useful for organizing as well.
There are some changes to the Photos app in Catalina, most notably how you browse your photos. Gone are the confusing Years, Collections and Moments views, replaced by the more understandable Years, Months and Days views. You can also see square thumbnails in the All Photos view, plus a few other improvements.
A lot of Mac and iOS users don't know that you can search for objects in your photos even if you have never added titles or keywords to your Photos Library. The app will indentify various types of items and scenery in photos. You can combine these category searches with locations and other search terms.
The color adjustment tools in Preview allow you to tint a photo, but without much control. By using this special technique, you can tint your photo any color you wish, and by any amount. You can also do this directly in the Photos app using the markup tools there. This is also a good way to fade a photo or to darken it without losing too much definition.
Instead of storing your videos in the Photos app with your pictures, consider storing them as files in a folder in the Finder. You can place this folder on your iCloud Drive, on your local drive only, or on an external drive. You can organize them using file names, subfolders, tags and comments. You can use the Gallery view to look through your videos almost as if they were in a special video management app.
You can use the Mac Photos app adjustment tools to make a blue sky in your pictures deeper and bluer. You can adjust pure blue, or select a color in the sky to make fine adjustments. You can also limit the range of the changes to keep other parts of your photo the same.
You can add captions to your photos right in the Photos app if you use the built-in Markup extension. You can add text and provide contrast between the text and the image. You can also add speech bubbles, lines and other elements. You can also do this to image files using Preview.
Since iOS 11 on the iPhone the default file format for photos has been HEIC. This is a new image file format that gives better compression and image quality than JPEG. On the Mac, the Photos app and macOS understands HEIC since High Sierra. In the Photos app you can use either HEIC or JPEG, and can export either as well. Other apps and devices also support HEIC.
It isn't always possible to take a photo at the location and angle that you want. But you can straighten the photo afterwards on your Mac using most major image editing tools. Learn how to change the perspective and straighten a photo in Pixelmator, Acorn and Photoshop.
Photos has a decent set of adjustment tools that you can use to change the mood of a photo. It is popular now to apply a bluish dark moody effect to photos and here are two ways to accomplish that. You can use light and color adjustments, or you can start with a filter and add some adjustments.
You can add a motion effect to a 2D photo without buying expensive software. By using Preview to cut a photo into layers and Keynote to animate them, you can make a photo come to life. This simple parallax animation effect can be used on all sorts of photos to create interesting videos or animated GIFs.
The photo editor in the Mac Photos app includes a lot of shortcuts that can help speed up editing, especially if you need to make adjustments to a range of photos. You can enter and exit editing mode quickly, move between photos without leaving the editor, jump to different editing modes, and compare the original to your adjustments easily. You can also fine-tune cropping and rotations.
You can create a photo collage using any number of apps and techniques on your Mac. But the quickest, but still very versatile, method is to use Keynote. You can easily drag and drop images from Photos onto a slide and arrange them with lines, borders, text and other elements. You can then export as an image.
If you are running out of storage space on your iPhone, you may think that removing some photos is a good way to free up space. But using iCloud Photo Library means that deleting a photo will delete it from all of your devices. The solution is not to try to delete a photo at all. You simply need to turn on Optimize iPhone Storage in your Photos settings. This will allow your iPhone to manage your photos so that only small thumbnails are stored for most photos. The original high-resolution photos will always be in iCloud, and can also be stored on your Mac. Optimizing allows you to get a lot of storage space back, while still having all of your photos available to you. You can do the same for your Mac or second Mac to save space.
If you want to watermark your photos before sharing them using a logo or other graphic, you can build a semi-transparent image in Pixelmator and then use an Automator Quick Action to easily apply that watermark to any image file. A special Pixelmator watermarking action helps to make it a one-step Automator workflow.
Apple has removed the direct link between the Photos app and Facebook in macOS Mojave. But it is still easy to upload Photos to Facebook using the Facebook website. You can use the Media option in the file open dialog, drag and drop into the file open dialog, drag directly onto the Facebook page, and a variety of other options. If you have trouble picking out a photo this way, you can always enlarge the photos you are viewing, or drag and drop direct from the Photos app or the Finder.
You can easily add captions and other elements to a photo right in the Photos app on your Mac. While there doesn't appear to be a captioning tool in Photos, you can edit a photo and use the default Markup extension to add text without leaving the app. You can always revert to the original photo or go back and edit your caption.
If you wish to have some of the photos on your Mac available in iCloud, but not others, a typical solution is to use two Photos libraries. But a more useful solution for some is to link some photos as referenced photos, keeping them separate from your Photos library while including them as linked photos. These items will not be synced to iCloud and will not be stored in your Mac's Photos library either. You can bring these photos into the library later on using the Consolidate command.
A quick and easy way to create a video slideshow with your photos is to use the built-in Slideshow function in the Photos app. You can just select some photos, stick with the defaults, and get a video to upload to YouTube or Facebook in less than a minute. Or, you can customize the theme, individual photos, text and more to create something a little more specific.