How do I enlarge my files when searching for images to upload to FB

When you open your Downloads folder click on View in the menubar and make sure that

Show Preview has been selected. Then when you highlight one of the images you will see an enlarge preview of it,

you can scale up or scale down the preview window size.

You could open your Downloads folder in icon view and then you can use the slider at the bottom of the window to enlarge the display of icons.

Or you can simply highlight the image and press the Spacebar, that will open the image in QuickView.

Or you can open your image files in the built in Preview app.

It's all jolly simple.

Your very first post asks only about enlarging files in the Finder, which I have answered.

Your last post now says "but I meant when I go into Facebook and hit photo and video to upload a photo"

that is a different question and down to Facebooks interface, which has nothing to do with Finder.

If Facebooks own upload interface does not allow you to enlarge the thumbnails of images

the best thing you can do is using the macs Finder, open the Downloads folder or the folder

the images are in, create a separate folder with an appropriate name and drag and drop only

the files you want to upload to Facebook into that new folder.

Now in Facebook you can use their upload interface to navigate to this new folder of images

and select them for upload.

Everything is the same you are just not doing it right.

Open your Downloads folder, select icon view

there are four different views you can select to view your files,

at the top of the window you will see this,

From the left they are Icon view, List view, Column view and Gallery view.

When you click on Icon view you will see the slider at the bottom of the window

When you have your Downloads folder open or any other Finder window you click on

View in the menubar and select Show Preview.

The advice I am giving you is correct, I am not going to give you bad advice.

You did say you were new to the mac.