If you're using the Overleaf editor to write your document, then you can upload images and position them pretty easily using the ' Add Media ' button in the editor.
Once you've inserted your image, you can drag it around to wherever you want it to go. If you want to change the way the image is aligned on the page, you can select it and then click on one of the alignment buttons in the toolbar above ( these are the little A, B, C buttons ).
If you want to add a caption to your image, you can select it and then click on the ' Insert/edit image ' button in the toolbar ( it looks like a tree ). This will open up the image properties dialogue, where you can add a caption.
