Hi there =)
When I export a photo and add effects or other in different apps, the size of the photo has downsized by more than half! I have the export settings in aperture set to keep original size but it shows up downsized in other applications. I can export a photo 17.9MP and it returns at 4.5MP and if I export at 4.5MP it returns at 1.1MP.
Please help! Tanya
You are welcome, Tanya, glad to help!
then select my photo/s from the aperture library or I drag and drop from aperture directly to the app on my desktop
Tanya, that explains it: If you drag and drop from Aperture, or import using the Media Browser (I think your "select my photo/s from the aperture library" means the Media Browser) then you will not use your "Export" presets. With both these methods the external editor will use the Previews of your images, not the high resolution master image files. The quality of your preview images depens on your settings in the "Preferences -> Preview" panel; usually this is set to for your screen size, but not good enough for high quality printing.
P.S.: Right now there is a funny bug with the export to an external editor, read this support article for a work around, if you do not see the results of your edits: http://support.apple.com/kb/TS4237