Bingo! That would help (and the result is like you see here, so we know who and what you're responding to).
I just took another, closer look at your sample image of the butterflies....
The highlights are "blown out" (no detail in the brightest/whitest areas of the image)... and there is strong purple fringing. Finally, sharpness and detail are okay, but could be better.
Regarding those aspects of your photo, I have four rather rhetorical questions:
1. Do you have a "protection" filter on the lens? Often stores will push those... and some folk like to use them. But lower quality, uncoated filters - in particular - can lead to image problems such as I've noted.
2. Are you using a lens hood? If not, one that's properly matched to the lens is highly advised. Does a better job physically protecting a lens than any thin glass filter ever could... Plus can improve image quality by keeping oblique light off the lens. And so long as it's a properly fitted one, a lens hood can never "harm" an image, the way shooting through a filter can.
3. What lens are you using? I really can't tell from the image EXIF and scanned your many previous responses, but didn't see info. All the above observations about your sample image also could be due to a lens' shortcomings. Someone else suggested you concentrate on upgrading your glass (lens) and not worry too much about upgrading the camera yet. That might be good advice. There's also something to be said for taking gear that you're familiar with on a long-awaited trip, so you don't have to spend your time figuring out how to use a new camera.
4. Have you had the camera's sensor cleaned or done so yourself? The reason I ask is because something that's often overlooked is that a dirty sensor also can lead to some of the image "issues" I noted above.... a dirty camera sensor makes for reduced sharpness and less fine detail. It also can lead to "blooming" and flare effects, if there are oils on the sensor (usually lubricants from the shutter mechanism).
Your T3i has a "self-cleaning" sensor feature that runs every time you turn the camera on or off. It's a great feature... but can only do so much. A careful and proper cleaning of the sensor is still needed, though a lot less often than with cameras that didn't have self-cleaning sensors. It's sometimes surprising how much difference you see in your images, after a good cleaning.
You can clean sensors yourself (see
www.cleaningdigitalcameras.com for more info).... and might want to invest in some of the stuff needed for that purpose anyway, to have with you "just in case". But it does need to be done properly and carefully... there's risk of doing damage to the camera if it's done wrong. If at all uncertain about doing it yourself, I recommend having a local professional camera repair tech do the cleaning. It usually costs $30 to $50, depending upon where you are. But it may be worth it to avoid some of the possible mistakes that can leave you without a camera for a while and with an expensive repair!
If you decide to try doing sensor cleanings yourself, you'll need to invest between $100 and $150 in the necessary supplies to do it right, but those will be enough for a number of cleanings so it will end up costing less per cleaning than having it done professionally. Just be sure to read everything at the link above, before tackling the job. The guys who maintain that site are professional repair techs themselves, as well as owning and operating Micro-Tools.com, one of the top suppliers to the camera repair industry. They pretty much sell everything for the purpose, so have some experience with it all and are fairly unbiased in their recommendations. Larry also has "written the book" on professional camera repair.... well actually many of them.
Bingo! That would help (and the result is like you... (