No further uploads required
If you are an OneDrive user, you can embed the photos that you’ve uploaded by using the Embed feature. It also gives you the flexibility to choose the image size and the final code to be used to embed into the blog post/web pages of your choice.
Usually, if you want to embed directly a photo into your blog post, you can leave the “Include HTML tags” checkbox unchecked, and directly copy the URL located below the checkbox.
I believe other storage providers, such as Google Drive and Dropbox provided a similar feature, but they will have a different implementation than that of OneDrive. And, Google Photos does not allow one to directly embed an image, which made me switched to OneDrive.
Beware of the photo metadata (i.e. personal information embedded in your photo!)
Beware, however, of the metadata (data that describes other data, of which in this case, is your photo) that is embedded in your photo, especially when your photo is uploaded from your smartphone. Sensitive metadata, such as GPS location of the captured photo, camera model used, etc. is usually included for ease of search in your phone. This, however, is risky to be exposed to the internet.
Fortunately, you can confirm whether the metadata is included in your photo by downloading the photo to be embedded by accessing the URL above. This will download a copy of the said photo into your local device, where you can verify it by right clicking your photo and navigate to the Properties tab (or its equivalent in other systems).