99.9999% of the downloads from the page you mention are illegal.
Is not allowed, but they do it anyways. Criminals keep on doing their business even though they know is not right. It is supposed there are copyright laws in many parts of the world, but some countries just don't enforce them. So they keep doing their illegal activities. Some of those criminals even hide behind statements like "freedom of the internet" and "sharing of knowledge" to justify their criminal activities. But is still piracy of intellectual work.
There are several issues with that kind of models:
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first, as illegal scans, they breach copyright laws and its distribution affects negatively the market of the original printed copies. And affects negatively the designers. That alone is a very important reason. The publishing houses depend on the sales of their kits to keep on the business. They devote only to that activity. And the less money they get, the more likely the will be forced out of the business. And if they disappear, there will be no one designing and publishing. Contrary to what some think, those are not huge international companies that can survive even with some piracy. You don't see Halinski, Orlik, GPM etc. having printing franchises in each European country. And there's a reason almost none of them offer instructions in a language other than Polish: Those are small local businesses and each kit they do not sell really means some euros less they have to pay their employees.
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second. Nothing guarantees those scans are good. In fact many are bad. You will always find mistakes in color, fit, accuracy, size, etc. It is a waste of time trying to build a pirate download, as there will always be distortion in the parts produced by the scanner. And differences in color. Sometimes small, sometimes big distortion. And nothing guarantees all the pages or all the parts are there. If there is a page missing or with bad shape, you can't complain. With an original printed copy you almost never have those issues (that is, unless the kit is badly designed to start with). And if a legal kit is damaged or incomplete, you can always ask support from the original designer or ask for a replacement from the publishing house.
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third, builds of illegal digital copies from those sites are frowned upon in this forum. Moderators and members alike always support the original designers and the original publishers. And allowing the build of a pirate copy to be shared here damages the hobby. If you wish to save yourself some trouble, just do not think on sharing your build of a pirate kit here. From the photo you show, you seem to be a good builder. Just imagine how much better your kit will look with using the original paper and the original inks of the kit.
When in doubt about the origin or legality of a kit, you can ask a moderator via private message. They're always to help. But a rule that almost always work is: If it is a download from those sites, it always is a pirate download. If it looks like a scan from a printed kit, it is an illegal copy and piracy. If it is a digital kit they redistribute and that was originally published by another site (like Yamaha or Canon) it is illegal.
In short: Just don't bother downloading from them. There are official electronic downloads from other sites that are free, some electronic downloads are paid in shops like
https://www.ecardmodels.com/ if you live in Spain or other Spanish speaking country, you will have easy access to the European publishers who release original kits. Just look for
http://papel3d.com/ store. Is a Spanish store. They are a good source of original kits, and you will be supporting the designers.
Finally:
Again, please write in English.
Moderators here speak English, and most of the users speak English too.
Only a handful of users understand Spanish.
If you don't know English, you can copy your text in google translate, and paste the English version here. Google translate is not perfect, but it helps a lot in the basic communication. Chances are that if you keep writing in a language almost no one understands here, your messages will be ignored and no one will be able to help you.