Not Sure if this was accurate but I read somewhere that ALF was finally discovered and caught and the show then ended. The pic below is "supposedly" the final scene of the series.

Yes this is true. Alf has an open end but he was only surrounded by the Alien Task Force not caught in the final scene. But as we learned later in the tv-Film-"Project: ALF",
Spoiler(select text):Alf was captured by the Alien Task Force.
By the way:In Germany, "Project: ALF" was shown in cinemas.

The final episode was meant to be a cliffhanger for a proposed fifth season. The writers were running out of scenarios involving ALF in the Tanner house, and came up with a new concept of ALF causing trouble in a military base. NBC made a deal with Paul Fusco's company that in the event the show got cancelled, a TV movie or special would be made to at least give ALF's story some closure.

Unfortunately, the new guy at NBC (who didn't know about the closure deal) decided to cancel ALF in order to make room for "The Fresh Prince of Bel Air". Luckily, ABC contact Paul Fusco a few years later to make the TV movie "Project ALF", which expanded the fifth season scenario, and gave the series an ending.

http://i.imgur.com/meEkfAv.png
This is the way it originally ended, and is seen as such on the german season 4 dvd set.

Yeah I actually saw that episode not even knowing it was the actual finale when it was already in the syndication run.

I think if a 5th season had happened it would've been the last competing against powerhouses like The Simpsons and Married With Children.

^Married With Children and the Simpsons weren't powerhouses at the time. FOX was a newer, up and coming network.

And yes, the final episode was open ended. You could watch it on Hulu.

I watched this episode first run when I was 7, I believe, as it ended in 1990. The last episode ended with "To Be Continued", then the show never came back. I just remember the last scene being very scary as I was just a little kid and when I watched it online/on DVD years later, it still looks that way as it was very dark and scary for ALF in the situation he had gotten into.

I got trouble watching that final it would been better if they all went up to melmac even the family then np with the alien force again just my thought

Well, ALF was trying to connect with Skip and Rhonda to go with them to New Melmac, but if the show had done that- that probably would have been the series finale, as that would have changed the whole show's dynamic and taken away the whole premise of the show itself- an alien living with the human family the Tanners.
Since the producers were hoping for a 5th. season with ALF causing havoc at a military base though, I guess that's why they went the direction they did- which certainly made for an interesting and intense season cliffhanger. But if that was the plan for a 5th. season, I guess the Tanner family would have been out of the situation altogether at that point. From what I've heard from interviews with the stars, that may have been just as well because I think they were pretty tired of the show and the long hours and other things.
Oh well- I think they wrapped up things well in the "Project: ALF" TV-movie. I love it! Maybe some of these things will be addressed in the ALF theatrical movie that Paul Fusco has said is coming soon. I would love to see the Tanners featured in the movie again though.
Anyway, for those who didn't like the TV show series finale episode (or at least the way it ended), you may enjoy checking out the last few issues of Marvel Comics' "ALF" comic. (Issues 47-50, specifically). The comic has a 4 part series finale that offers an alternate take on the show's series finale- I rather like it. It works well- (keep in mind that it was written before "Project: ALF" came about.)
The whole run of the ALF comic book series is well worth checking out- after a long while of looking, I was finally able to acquire the whole run- many times I find myself laughing out loud reading it. :) :cool:

Yeah, I saw the final episode on The Hub. ALF got caught although it was emotional with the Tanners saying good bye to ALF.