I wish for a cloning tool to eliminate unwanted from my photos at times. Can not locate within my I-Photo app.

You need a stronger photo editor - iPhoto has no "clone" tool - PhotoShop Elements has a great one

LN

You can use both Photoshop and Gimp, and many other, photo editors on your Mac.

In order of price here are some suggestions:

Seashore (free)

The Gimp (free)

Graphic Coverter ($45 approx)

Acorn ($50 approx)

Pixelmator ($50 approx)

Photoshop Elements ($75 approx)

There are many, many other options. Search on MacUpdate or the App Store.

You can set Photoshop (or any image editor) as an external editor in iPhoto. (Preferences -> General -> Edit Photo: Choose from the Drop Down Menu.) This way, when you double click a pic to edit in iPhoto it will open automatically in Photoshop or your Image Editor, and when you save it it's sent back to iPhoto automatically. This is the only way that edits made in another application will be displayed in iPhoto.

Touch-up is not the solution i.e. to eliminate overhead wiring, hydrants, signs and so on. Photoshop shows, Gimp as well. I cannot use either software on my Mac

Gimp is free on your Mac - see TD's list. If you only need a very smart tool for cloning background to remove objects by cloning background from the same photo consider "inPaint". It is very simple to use. Just brush across the objects you want to be removed. inPaint replaces automatically selected structures by the most similar background based on statistical measures. See this link:

http://www.theinpaint.com

Another option would be Aperture's clone and retouch brushes. Using Aperture would have one big advantage to the external editors - aperture and iPhoto can work on the same photo library. If you open your iPhoto library in Aperture, all edits will be lossless and can be reverted step by step. iPhoto understands the edits Aperture has done.