For Mac users.
To adjust the size of the photo in Mac just open the picture with preview go to "Tools" on the toolbar then "Adjust size" a popup window appears change the width and height will automatically change as well as it has the "lock" aspect fixed.File Size of picture will be displayed in the window as well (below) ajust till you get the size file for upload limits, keep resolution up to 72 dpi for ok pics on the web changing this also changes file size,higher larger file ,Hit ok. Go to "file" then "save as" note file type you want to save in and change name if you want to keep the old large file prior save back to a new folder or the old one with new name so you don't delete the good high definition original.
file size upload limits vary depending on format you save the picture in pdf.jpeg bitmap etc. just look it up on the website it is listed.
I can only post one picture of one or two I can send one with same I phone that took picture I didn't have this trouble with my android phone . like poster said I got other things to do than play on this thing trying to figure it out .