There seems to be some confusion about current mirrors. Here is a basic current mirror:
Some part of the circuit produces current, which is dumped onto IN. OUT then becomes a sink for the same amount of current, which is where the term mirror comes from.
Look carefully at how this works. Assume both transistors are identical. The base voltage of Q2 will be whatever it takes so that its collector draws the current being dumped onto it. Since Q1 is identical to Q2, this is also the same base voltage so that Q1 tries to sink the same current. The matching between the transistors must be pretty close for this not to be wildly off, since the base of Q1 is being voltage driven. The B-E junction is a diode, so the current can vary a lot for small changes of voltage.
On a IC this matching will be close enough to be useful, since the whole IC is subjected to the same process variations. This is not a good circuit if you are building it yourself from discrete parts. In that case you add two resistors to make things much more accurate and less dependent on the individual characteristics of the two transistors:
Due to the resistors, the function of base voltage to collector current becomes more predictable. The downside is that the resistors eat up a little voltage, but a little helps a lot. Even if the resistors drop 500 mV at the maximum current, the error from input current to output current will be much better than with no resistors.
Now note that the two resistors need not be equal. If we consider the B-E voltage of the two transistors fixed, then the ratio of output current to input current will be R1/R2. If R2 is half of R1, for example, then the mirror will want to sink twice the current at OUT that you put in to IN. At high ratios you need to let the resistors drop a bit more voltage to get reasonably linear operation since there will be more variation of the B-E drop between the two resistors. It is a tradeoff between voltage lost in the resistors to accuracy, but this circuit will work well enough for many purposes when built from discrete parts.
Note that if the objective is to multiply a current signal by a fixed gain, there are other ways to do this than with a current mirror.