Both are correct with different meaning. The perfect ( have uploaded) is for action completed in the present: I have uploaded the files, the job is done now. The pluperfect ( had uploaded) is used for action completed in the past: I had uploaded the files before you asked me to.
No. It is not a sentence, but a dependent clause.
"Not like that" can be grammatically correct, depending on the context.
Yes! That is grammatically correct!
Yes, 'for free', is grammatically correct.
This is not grammatically correct. The correct form is 'you do not know', or the abbreviated 'you don't know'.
The Kindle can read PDF files uploaded from a USB memory stick.
'Once photos are uploaded' and 'once photos have been uploaded' are probably both correct, but I would use once photos have been uploaded
Sure. It would also be grammatically correct to write He spoggled his nubbix on the goober. Grammatically correct and meaningful are not the same.
'What a drunkard you are' is a grammatically correct English sentence.
"That was wrong" is a grammatically correct sentence.
Yes, Almighty God is grammatically correct.
Yes, it is grammatically correct.