Kunezinhlobo zezifomethi zesithombe ezingasetshenziswa kumakhasi ewebhu. Ezinye izibonelo ezivamile ziyi- GIF , i- JPG , ne- PNG . Amafayela we-SVG abuye asetshenziswe kakhulu kumawebhusayithi namuhla, enikeza abakhi bewebhu nenye indlela yokwenza isithombe se-intanethi.
Izithombe ze-GIF
Sebenzisa amafayela we-GIF ngezithombe ezinenani elincane, elihleliwe lemibala. Amafayela we-GIF ahlale ehlisiwe angaphezu kwama-256 imibala ehlukile. I-algorithm yokucindezela yamafayela we-GIF ayinkimbinkimbi kakhulu kunamafayela we-JPG, kodwa uma isetshenziswe emifanekisweni emibala enombala futhi ibhala iveza ubukhulu obukhulu befayela .
Ifomethi ye-GIF ayifanele imifanekiso yezithombe noma izithombe ezinemibala ye-gradient. Ngenxa yokuthi ifomethi ye-GIF inenani elilinganiselwe lemibala, ama-gradients nezithombe zizophela nge-banding ne-pixelation uma igcinwa njengefayela le-GIF.
Ngamafuphi, ungasebenzisa ama-GIF kuphela ngemifanekiso elula enemibala embalwa nje kuphela, kodwa ungasebenzisa futhi i-PNGs ngaleyo ndlela (ngaphezulu kwalokho ngokushesha).
Izithombe ze-JPG
Sebenzisa izithombe ze-JPG zezithombe nezinye izithombe ezinemibala eminingi. Isebenzisa i-complex compression algorithm evumela ukuthi udale ihluzo ezincane ngokulahlekelwa ezinye zekhwalithi yesithombe. Lokhu kubizwa ngokuthi "ukulahleka" ukucindezela ngoba olunye ulwazi lwedatha lulahlekile lapho isithombe sicindezelekile.
Ifomethi ye-JPG ayifaneleki izithombe ezinombhalo, amabhlogo amakhulu wombala oqinile, namajamo alula ngamaphethelo aphikisayo. Lokhu kungenxa yokuthi uma isithombe sicindezelekile, umbhalo, umbala, noma imigqa ingase idideke ngenxa yalokho okungekho ebukhali njengoba kungasindiswa kwenye ifomethi.
Izithombe ze-JPG zisebenziseka kakhulu ezithombeni nezithombe ezinemibala eminingi nemvelo eminingi.
Izithombe ze-PNG
Ifomethi ye-PNG yasungulwa njenge-esikhundleni sefomethi ye-GIF uma kubonakala ukuthi izithombe ze-GIF ziyobekwa ngaphansi kwemali yobukhosi. Ihluzo ze-PNG zinenani elingcono lokucindezela kunezithombe ze-GIF ezenza izithombe ezincane kunefayela elifanayo elondolozwe njenge-GIF. Amafayela we-PNG anikeza ukukhanya kwe-alpha, okusho ukuthi ungaba nezindawo zezithombe zakho ezibonakala ngokugcwele noma ngisho nokusebenzisa ububanzi be-alpha obala. Isibonelo, isithunzi sokudonsa sisebenzisa ububanzi bezinto ezibonakalayo futhi kuzofanelekela i-PNG (noma ungase usiqede nje usebenzisa ama-CSS shad esikhundleni).
Izithombe ze-PNG, njenge-GIFs, azihambisani kahle nezithombe. Kungenzeka ukuthi uzungeze inkinga ye-banding ethinta izithombe ezigcinwe njengezifayili ze-GIF usebenzisa imibala yeqiniso, kodwa lokhu kungaholela ezithombeni ezinkulu kakhulu. Izithombe ze-PNG nazo azixhaswa kahle ngamafoni asebekhulile namafoni wesici.
Sisebenzisa i-PNG kunoma yiliphi ifayela elidinga ukubonakala. Siphinde sisebenzise i-PNG-8 kunoma yiliphi ifayela elizofaneleka njenge-GIF, besebenzisa le fomethi ye-PNG esikhundleni.
SVG Izithombe
I-SVG imele i-Scalable Vector Graphic. Ngokungafani namafomethi e-raster asekelwe ku-JPG, GIF, ne-PNG, lawa mafayela asebenzisa ama-vectors ukudala amafayela amancane kakhulu angatholakala kunoma yisiphi isayizi ngaphandle kokulahlekelwa kwekhwalithi yokwanda kobukhulu befayela. Zidalwa ngemifanekiso efana nezimpawu ngisho nama-logos.
Ukulungiselela Izithombe Zokuletha Iwebhu
Kungakhathaliseki ukuthi usebenzise ifomethi yesithombe, futhi iwebhusayithi yakho izokusebenzisa inombolo yamafomethi ahlukene kuwo wonke amakhasi ayo, udinga ukuqinisekisa ukuthi zonke izithombe kulesi sayithi zilungiselelwe ukulethwa kwewebhu . Izithombe ezinkulu kakhulu zingabangela isayithi ukuthi isebenze kancane futhi ithinte ukusebenza jikelele. Ukulwa nalokhu, lezo zithombe kufanele zenziwe kahle ukuze zithole ibhalansi phakathi kwekhwalithi ephakeme kanye nosayizi wefayela ophansi kunazo zonke ezingenzeka kuleveli yekhwalithi.
Ukukhetha imidwebo yezithombe ezilungile yingxenye yempi, kodwa futhi ukuqinisekisa ukuthi ulungiselele lawo mafayela yisinyathelo esilandelayo kule nqubo ebalulekile yokuletha iwebhu.
Isihloko sokuqala sikaJennifer Krynin. Ihlelwe nguJeremy Girard.