C#

    intCollection iCollection=...;
    // determine int range
    int imin=int.MaxValue;
    int imax=int.MinValue;
    foreach(int i in iCollection) {
        if (i<imin) imin=i;
        if (i>imax) imax=i;
    }
    // determine scaling factors
    float fmin=0.0;
    float fmax=1.0;
    float scale=(fmax-fmin)/(imax-imin);
    // scale
    floatCollection fCollection=...; // empty
    foreach (int i in iCollection) {
        float f=fmin+(i-imin)*scale;   // <<<<<<<<<<<<<< bug fixed
        fCollection.Add(f);
    }
}

openFileDialog1.Filter = "Images|*.jpg;*.gif;*.png|All files|*.*";