Same here. It's been doing that since V2.2.0, on DVD playback and also playing IPTV and DVB-T (which thankfully plays well again otherwise) television. For example, a regular SD widescreen 16:9 source used to result in snapshot dimensions of 1024x576, and 4:3 source in 768x576, now it's always 704x576 or 720x576 depending on the original broadcast source. (HD television is not affected here, i.e. a 720p broadcast snapshot is 1280x720 like it should.)
I thought this should be a feature more than a bug (so technically that's a good thing), because in Advanced Settings -> Video -> Snapshot there's a "width" and "height" setting to override the aspect ratio of the output snapshot. Both are set to "-1" here. But I've been playing with this setting, putting in "0" and such, and it seems to have no effect. I always just get the snapshot dimensions mentioned above.
Another snapshot issue that's new is VLC apparently doesn't handle the timestamp naming of snapshots correctly anymore. If I'd have to guess, I think this started with the daylight savings time switch - earlier in March, this worked fine, now it doesn't anymore. If it is related to DST, then it obviously may be system-specific, so: I'm on Win7 Pro /w SP1, 64bit.
For example for snapshots taken just seconds apart, I used to get correct names like this:
vlcsnap-2015-03-14-08h04m01s275.png
vlcsnap-2015-03-14-08h04m10s020.png
vlcsnap-2015-03-14-08h04m15s735.png
Now I'm getting snapshot names like this:
vlcsnap-3558-06-03-03h30m34s553.png
vlcsnap-5219-12-26-11h30m52s438.png
vlcsnap-6931-02-11-14h19m57s588.png
Which obviously doesn't make sense.
![Surprised :o](./images/smilies/icon_surprised.gif)