You asked for photos of interiors of locos and so far no one who has answered your post has provided you any. Nor Can I. It would, for someone with a digital camera, require lots of their time and effort to dismantle their locos and photograph them just for you. Then it would also require someone who happened to have locos of varying price ranges to do so for you. You are asking a lot of someone's time.
People can, however, easily enough offer experiences and knowlege of locos in the hobby form personal experience or through reading the forums. That is all I can offer.
LifeLike Locos are noted to be cheapy train set quality {not good} and most all serious modelers would avoid them.
Bachmann's were once noted as cheapy crap and the bottom of the barrel shared with LifeLike. TOday, however, Bachmann quality has changed and Bachmann has worked
very hard to change it's image and it's products. They came out with the "SPectrum" line of locos which were designed to be more detailed and of higher quality. MAny of their regular lines, however, now share the spotlight of good quality with the Spectrums, and many spectrums become the standard line as time marches on. The "DCC OnBoard" locos range from the simple low price DCC controlled direction, speed and lighting to more expensive Spectrums with sound as well as more DCC functions.
I have several of the Bachmann Standard DCC OnBoard locos...inexpensive and DCC controled for speed, light and direction-my basic requirements- and am very happy with all of them and have not had a problem with a single one.
One other note of fact: It seems Bachmann has made quite a name for itself on the warrantee end of things. They do well to repair/replace locos under warrantee, even out of warrantee, even "if you worked on it first", they no longer manufacture that model, or "you broke it", often totally free of charge,in a timely manner, and In their Philly, PA USA warrantee center.
Atlas, Athearn and others have lower priced and higher priced locos. MAny are happy with their locos from these companies, others wouldn't buy them again due to having a bad one in the bunch. MAny treasure the Blue Box locos and wouldn't buy anything else if they could avoid it.They have mixed reviews. I am unsure how they handle warrantee repairs as I simply do not recall having read of them. That does not necessarily equate to good quality.
BLI {expensive} on the other hand, appears to be a bit of a crap shoot-you may get a good one lasting forever, or you get a bad one that haunts you and according to at least one fellow, apparently requires one to pay partial costs of repair/replace including shipping and in this case the guy reported returning his beloved BLI {expensive} loco 6 times, with 2 replacements and STILL he reported it failed yet again.
MTH trains{expensive}
really wants you to order and pay for their proprietary DC
S system. Their loco's will run, in limited capacity, on standardized DCC systems. MTH could have done well to make their locos DCC Compliant. Few have reported yet on their experiences with failures as fewer buy these locos apparently due to the DCS/DCC issue. A few have reported happy with their aquisitions of MTH, though have mentioned the limits fo the locos on DCC systems. There may have been few failures, or few reports on how MTH handles its issues.
The theory that the more expensive the loco, the better the quality is out the window as there are QC issues with all brands and all manufacturers and it does well to remember they are all made in China, and Chinese Quality has apparently decreased of late. Even when products were manufactured in the USA, there were still QC issues and bad batches.
It also is worth noting that as the value of the dollar fluctuates, so does the price of locos. ANd the advancements of ready to run DCC and sound systems has added grossly to the cost of a loco-that is over the cost of a DC loco and a DCC decoder with sound that one could install themselves if they are so adept.
It often comes down to what happens after the sale when there is a problem that counts, regardless of price.

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Rock_Babe