Switch image on button press for gallery.

Question

The image is not changing. The images wont show up as they are local files so will have too switch them to show in Sololearn.
https://code.sololearn.com/WoI1BlzxKtQ8/#html

Answer 1

Your functions are incrementing/decrementing picPos beyond the bounds of the pictures array.
I substituted a couple of picture addresses in the pictures array and changed the static img src so that it matched the address at pictures[0] and then changed your functions so that when either end of the array was reached picPos was set to the value at the opposite end of the array depending on which button was clicked. This effectively will just loop through the pictures in the array.

function picSwitchForward(){
if(picPos >= pictures.length-1)
picPos = 0;
else
picPos++;
changePic(picPos);
}
function picSwitchBack(){
if(picPos <= 0)
picPos = pictures.length - 1;
else
picPos--;
changePic(picPos);
}
function changePic(picPos) {
document.getElementById("picture").src = pictures[picPos];
}